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BoP Lab / Classes / FA

FA vs AS vs FV vs EP pace at every track

Lap times across years say as much about the weather as the class. % of FA is each class's best lap as a share of FA's on the same day, so the conditions drop out: 100% is level, less is quicker, and a move in it is the class getting faster or slower against the field.

Class · click a class to switch, + to compare alongside (up to 4: remove one to add another)
Series
Reference class · the yardstick the % column and chart are measured against
Tracks · untick to narrow

Quickest here: FA 1:14.920 Ryan Norman, Runoffs 2016 qualifying · AS 1:30.651 Tom Sloe, Runoffs 2016 qualifying · FV 1:37.942 Alex Scaler, Runoffs 2016 qualifying · EP 1:33.847 Michael Galati, Runoffs 2016 qualifying

1:402:002:202:4027 rule changes between Runoffs 2018 and Runoffs 201927 ▾51 rule changes between Runoffs 2019 and Runoffs 202051 ▾50 rule changes between Runoffs 2020 and Runoffs 202150 ▾41 rule changes between Runoffs 2021 and Runoffs 202241 ▾24 rule changes between Runoffs 2022 and Runoffs 202324 ▾27 rule changes between Runoffs 2023 and Runoffs 202427 ▾28 rule changes between Runoffs 2024 and Runoffs 202528 ▾41 rule changes between Runoffs 2025 and Runoffs 202641 ▾FA race best at Runoffs 2015: 1:48.162 (Tyler Hunter)Off the chart: FA race best at Runoffs 2016: 1:19.009 (Ryan Norman)FA race best at Runoffs 2017: 1:31.365 (Keith Grant)FA race best at Runoffs 2018: 1:29.924 (Mirl Swan)FA race best at Runoffs 2019: 1:43.107 (Dario Cangialosi)FA race best at Runoffs 2020: 2:04.746 (Spencer Brockman)FA race best at Runoffs 2021: 1:30.650 (James French)FA race best at Runoffs 2022: 1:48.507 (Alex Mayer)FA race best at Runoffs 2024: 2:01.790 (Dudley Fleck)FA race best at Runoffs 2025: 2:02.654 (Hans Peter)FA race best at Runoffs 2026: 2:03.334 (James French)FA qualifying best at Runoffs 2015: 1:47.758 (Tyler Hunter)Off the chart: FA qualifying best at Runoffs 2016: 1:14.920 (Ryan Norman)FA qualifying best at Runoffs 2017: 1:29.957 (Sedat Yelkin)FA qualifying best at Runoffs 2018: 1:28.176 (Mirl Swan)FA qualifying best at Runoffs 2019: 1:41.545 (Dario Cangialosi)FA qualifying best at Runoffs 2020: 2:04.274 (Spencer Brockman)FA qualifying best at Runoffs 2021: 1:29.701 (James French)FA qualifying best at Runoffs 2022: 1:44.703 (Chip Romer)FA qualifying best at Runoffs 2024: 2:01.560 (Hans Peter)FA qualifying best at Runoffs 2025: 2:00.923 (Hans Peter)FA qualifying best at Runoffs 2026: 2:02.513 (Dudley Fleck)AS race best at Runoffs 2015: 2:02.922 (Andy McDermid)AS race best at Runoffs 2016: 1:33.424 (Edward Hosni)AS race best at Runoffs 2017: 1:51.507 (Bryan Long)AS race best at Runoffs 2018: 1:50.345 (John Heinricy)AS race best at Runoffs 2019: 2:03.900 (James Jost)AS race best at Runoffs 2020: 2:27.668 (Gregory Eaton)AS race best at Runoffs 2021: 1:50.606 (Gregory Eaton)AS race best at Runoffs 2022: 2:04.578 (Gregory Eaton)AS race best at Runoffs 2023: 2:04.120 (Gregory Eaton)AS race best at Runoffs 2024: 2:26.429 (Gregory Eaton)AS race best at Runoffs 2025: 2:29.232 (Gregory Eaton)AS race best at Runoffs 2026: 2:28.471 (Andrew McDermid)AS qualifying best at Runoffs 2015: 2:01.746 (Tom Sloe)AS qualifying best at Runoffs 2016: 1:30.651 (Tom Sloe)AS qualifying best at Runoffs 2017: 1:45.220 (James Jost)AS qualifying best at Runoffs 2018: 1:47.782 (Andrew McDermid)AS qualifying best at Runoffs 2019: 2:02.938 (Gregory Eaton)AS qualifying best at Runoffs 2020: 2:27.045 (Gregory Eaton)AS qualifying best at Runoffs 2021: 1:50.427 (Drew Cattell)AS qualifying best at Runoffs 2022: 2:02.162 (Kurt Rezzetano)AS qualifying best at Runoffs 2023: 2:03.082 (Daniel Richardson)AS qualifying best at Runoffs 2024: 2:26.578 (Gregory Eaton)AS qualifying best at Runoffs 2025: 2:26.792 (Andrew McDermid)AS qualifying best at Runoffs 2026: 2:26.911 (Andrew McDermid)FV race best at Runoffs 2015: 2:21.142 (Andrew Whitston)FV race best at Runoffs 2016: 1:38.066 (Flinn Lazier)FV race best at Runoffs 2017: 1:55.923 (Michael Varacins)FV race best at Runoffs 2018: 1:53.639 (Alex Scaler)FV race best at Runoffs 2019: 2:18.289 (Zachary Whitston)FV race best at Runoffs 2020: 2:45.816 (Alex Scaler)FV race best at Runoffs 2021: 1:57.234 (Alex Scaler)FV race best at Runoffs 2022: 2:18.093 (Andrew Whitston)FV race best at Runoffs 2023: 2:16.611 (Andrew Abbott)FV race best at Runoffs 2024: 2:44.834 (Andrew Abbott)FV race best at Runoffs 2025: 2:46.736 (Zachary Whitston)FV race best at Runoffs 2026: 2:45.272 (Brian Farnham)FV qualifying best at Runoffs 2015: 2:21.167 (Roger Siebenaler)FV qualifying best at Runoffs 2016: 1:37.942 (Alex Scaler)FV qualifying best at Runoffs 2017: 1:55.759 (Michael Varacins)FV qualifying best at Runoffs 2018: 1:52.637 (Skip Streets)FV qualifying best at Runoffs 2019: 2:15.712 (Andrew Whitston)FV qualifying best at Runoffs 2020: 2:43.994 (Hunter Phelps-Barron)FV qualifying best at Runoffs 2021: 1:57.479 (Andrew Whitston)FV qualifying best at Runoffs 2022: 2:15.116 (Brian Farnham)FV qualifying best at Runoffs 2023: 2:15.639 (Andrew Whitston)FV qualifying best at Runoffs 2024: 2:42.643 (Andrew Whitston)FV qualifying best at Runoffs 2025: 2:44.101 (Andrew Abbott)FV qualifying best at Runoffs 2026: 2:46.536 (Zachary Whitston)EP race best at Runoffs 2015: 2:05.109 (Kip Van Steenburg)EP race best at Runoffs 2016: 1:34.266 (Michael Galati)EP race best at Runoffs 2017: 1:50.396 (Matt Reynolds)EP race best at Runoffs 2018: 1:46.518 (Glen McCready)EP race best at Runoffs 2019: 2:01.631 (Jesse Prather)EP race best at Runoffs 2020: 2:29.047 (Jesse Prather)EP race best at Runoffs 2021: 1:49.928 (Jesse Prather)EP race best at Runoffs 2022: 2:30.855 (Jesse Prather)EP race best at Runoffs 2023: 2:04.050 (Greg Ira)EP race best at Runoffs 2024: 2:27.869 (Tyler Ladd)EP race best at Runoffs 2025: 2:28.756 (Tyler Ladd)EP race best at Runoffs 2026: 2:27.869 (Jon Brakke)EP qualifying best at Runoffs 2015: 2:03.794 (Kip Van Steenburg)EP qualifying best at Runoffs 2016: 1:33.847 (Michael Galati)EP qualifying best at Runoffs 2017: 1:49.597 (Matt Reynolds)EP qualifying best at Runoffs 2018: 1:45.828 (Glen McCready)EP qualifying best at Runoffs 2019: 2:00.987 (Jesse Prather)EP qualifying best at Runoffs 2020: 2:27.322 (Jesse Prather)EP qualifying best at Runoffs 2021: 1:48.181 (Jesse Prather)EP qualifying best at Runoffs 2022: 2:02.326 (Jesse Prather)EP qualifying best at Runoffs 2023: 2:03.215 (John Hainsworth)EP qualifying best at Runoffs 2024: 2:26.803 (Tyler Ladd)EP qualifying best at Runoffs 2025: 2:27.293 (Jon Brakke)EP qualifying best at Runoffs 2026: 2:29.239 (Jon Brakke)Daytona International Speedway · Runoffs 2015R2015Mid-Ohio Sports Car Course · Runoffs 2016R2016Indianapolis Motor Speedway · Runoffs 2017R2017Sonoma Raceway · Runoffs 2018R2018Virginia International Raceway · Runoffs 2019R2019Road America · Runoffs 2020R2020Indianapolis Motor Speedway · Runoffs 2021R2021Virginia International Raceway · Runoffs 2022R2022Virginia International Raceway · Runoffs 2023R2023Road America · Runoffs 2024R2024Road America · Runoffs 2025R2025Road America · Runoffs 2026R2026
FAASFVEPsolid race · dashed qualifying · slower is lower
100%110%120%130%27 rule changes between Runoffs 2018 and Runoffs 201927 ▾51 rule changes between Runoffs 2019 and Runoffs 202051 ▾50 rule changes between Runoffs 2020 and Runoffs 202150 ▾41 rule changes between Runoffs 2021 and Runoffs 202241 ▾24 rule changes between Runoffs 2022 and Runoffs 202324 ▾27 rule changes between Runoffs 2023 and Runoffs 202427 ▾28 rule changes between Runoffs 2024 and Runoffs 202528 ▾41 rule changes between Runoffs 2025 and Runoffs 202641 ▾FA race best at Runoffs 2015: 100.0% of FA's (Tyler Hunter)FA race best at Runoffs 2016: 100.0% of FA's (Ryan Norman)FA race best at Runoffs 2017: 100.0% of FA's (Keith Grant)FA race best at Runoffs 2018: 100.0% of FA's (Mirl Swan)FA race best at Runoffs 2019: 100.0% of FA's (Dario Cangialosi)FA race best at Runoffs 2020: 100.0% of FA's (Spencer Brockman)FA race best at Runoffs 2021: 100.0% of FA's (James French)FA race best at Runoffs 2022: 100.0% of FA's (Alex Mayer)FA race best at Runoffs 2024: 100.0% of FA's (Dudley Fleck)FA race best at Runoffs 2025: 100.0% of FA's (Hans Peter)FA race best at Runoffs 2026: 100.0% of FA's (James French)FA qualifying best at Runoffs 2015: 100.0% of FA's (Tyler Hunter)FA qualifying best at Runoffs 2016: 100.0% of FA's (Ryan Norman)FA qualifying best at Runoffs 2017: 100.0% of FA's (Sedat Yelkin)FA qualifying best at Runoffs 2018: 100.0% of FA's (Mirl Swan)FA qualifying best at Runoffs 2019: 100.0% of FA's (Dario Cangialosi)FA qualifying best at Runoffs 2020: 100.0% of FA's (Spencer Brockman)FA qualifying best at Runoffs 2021: 100.0% of FA's (James French)FA qualifying best at Runoffs 2022: 100.0% of FA's (Chip Romer)FA qualifying best at Runoffs 2024: 100.0% of FA's (Hans Peter)FA qualifying best at Runoffs 2025: 100.0% of FA's (Hans Peter)FA qualifying best at Runoffs 2026: 100.0% of FA's (Dudley Fleck)AS race best at Runoffs 2015: 113.6% of FA's (Andy McDermid)AS race best at Runoffs 2016: 118.2% of FA's (Edward Hosni)AS race best at Runoffs 2017: 122.0% of FA's (Bryan Long)AS race best at Runoffs 2018: 122.7% of FA's (John Heinricy)AS race best at Runoffs 2019: 120.2% of FA's (James Jost)AS race best at Runoffs 2020: 118.4% of FA's (Gregory Eaton)AS race best at Runoffs 2021: 122.0% of FA's (Gregory Eaton)AS race best at Runoffs 2022: 114.8% of FA's (Gregory Eaton)AS race best at Runoffs 2024: 120.2% of FA's (Gregory Eaton)AS race best at Runoffs 2025: 121.7% of FA's (Gregory Eaton)AS race best at Runoffs 2026: 120.4% of FA's (Andrew McDermid)AS qualifying best at Runoffs 2015: 113.0% of FA's (Tom Sloe)AS qualifying best at Runoffs 2016: 121.0% of FA's (Tom Sloe)AS qualifying best at Runoffs 2017: 117.0% of FA's (James Jost)AS qualifying best at Runoffs 2018: 122.2% of FA's (Andrew McDermid)AS qualifying best at Runoffs 2019: 121.1% of FA's (Gregory Eaton)AS qualifying best at Runoffs 2020: 118.3% of FA's (Gregory Eaton)AS qualifying best at Runoffs 2021: 123.1% of FA's (Drew Cattell)AS qualifying best at Runoffs 2022: 116.7% of FA's (Kurt Rezzetano)AS qualifying best at Runoffs 2024: 120.6% of FA's (Gregory Eaton)AS qualifying best at Runoffs 2025: 121.4% of FA's (Andrew McDermid)AS qualifying best at Runoffs 2026: 119.9% of FA's (Andrew McDermid)FV race best at Runoffs 2015: 130.5% of FA's (Andrew Whitston)FV race best at Runoffs 2016: 124.1% of FA's (Flinn Lazier)FV race best at Runoffs 2017: 126.9% of FA's (Michael Varacins)FV race best at Runoffs 2018: 126.4% of FA's (Alex Scaler)FV race best at Runoffs 2019: 134.1% of FA's (Zachary Whitston)FV race best at Runoffs 2020: 132.9% of FA's (Alex Scaler)FV race best at Runoffs 2021: 129.3% of FA's (Alex Scaler)FV race best at Runoffs 2022: 127.3% of FA's (Andrew Whitston)FV race best at Runoffs 2024: 135.3% of FA's (Andrew Abbott)FV race best at Runoffs 2025: 135.9% of FA's (Zachary Whitston)FV race best at Runoffs 2026: 134.0% of FA's (Brian Farnham)FV qualifying best at Runoffs 2015: 131.0% of FA's (Roger Siebenaler)FV qualifying best at Runoffs 2016: 130.7% of FA's (Alex Scaler)FV qualifying best at Runoffs 2017: 128.7% of FA's (Michael Varacins)FV qualifying best at Runoffs 2018: 127.7% of FA's (Skip Streets)FV qualifying best at Runoffs 2019: 133.6% of FA's (Andrew Whitston)FV qualifying best at Runoffs 2020: 132.0% of FA's (Hunter Phelps-Barron)FV qualifying best at Runoffs 2021: 131.0% of FA's (Andrew Whitston)FV qualifying best at Runoffs 2022: 129.0% of FA's (Brian Farnham)FV qualifying best at Runoffs 2024: 133.8% of FA's (Andrew Whitston)FV qualifying best at Runoffs 2025: 135.7% of FA's (Andrew Abbott)FV qualifying best at Runoffs 2026: 135.9% of FA's (Zachary Whitston)EP race best at Runoffs 2015: 115.7% of FA's (Kip Van Steenburg)EP race best at Runoffs 2016: 119.3% of FA's (Michael Galati)EP race best at Runoffs 2017: 120.8% of FA's (Matt Reynolds)EP race best at Runoffs 2018: 118.5% of FA's (Glen McCready)EP race best at Runoffs 2019: 118.0% of FA's (Jesse Prather)EP race best at Runoffs 2020: 119.5% of FA's (Jesse Prather)EP race best at Runoffs 2021: 121.3% of FA's (Jesse Prather)EP race best at Runoffs 2022: 139.0% of FA's (Jesse Prather)EP race best at Runoffs 2024: 121.4% of FA's (Tyler Ladd)EP race best at Runoffs 2025: 121.3% of FA's (Tyler Ladd)EP race best at Runoffs 2026: 119.9% of FA's (Jon Brakke)EP qualifying best at Runoffs 2015: 114.9% of FA's (Kip Van Steenburg)EP qualifying best at Runoffs 2016: 125.3% of FA's (Michael Galati)EP qualifying best at Runoffs 2017: 121.8% of FA's (Matt Reynolds)EP qualifying best at Runoffs 2018: 120.0% of FA's (Glen McCready)EP qualifying best at Runoffs 2019: 119.1% of FA's (Jesse Prather)EP qualifying best at Runoffs 2020: 118.5% of FA's (Jesse Prather)EP qualifying best at Runoffs 2021: 120.6% of FA's (Jesse Prather)EP qualifying best at Runoffs 2022: 116.8% of FA's (Jesse Prather)EP qualifying best at Runoffs 2024: 120.8% of FA's (Tyler Ladd)EP qualifying best at Runoffs 2025: 121.8% of FA's (Jon Brakke)EP qualifying best at Runoffs 2026: 121.8% of FA's (Jon Brakke)Daytona International Speedway · Runoffs 2015R2015Mid-Ohio Sports Car Course · Runoffs 2016R2016Indianapolis Motor Speedway · Runoffs 2017R2017Sonoma Raceway · Runoffs 2018R2018Virginia International Raceway · Runoffs 2019R2019Road America · Runoffs 2020R2020Indianapolis Motor Speedway · Runoffs 2021R2021Virginia International Raceway · Runoffs 2022R2022Virginia International Raceway · Runoffs 2023R2023Road America · Runoffs 2024R2024Road America · Runoffs 2025R2025Road America · Runoffs 2026R2026
FAASFVEPsolid race · dashed qualifying · each class's best lap as a share of FA's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker
EventFAASFVEP
Qual bestRace bestTrapQual bestRace bestTrapvs FA% of FAQual bestRace bestTrapvs FA% of FAQual bestRace bestTrapvs FA% of FA
Road America Runoffs 20262026-09-282:02.513Dudley Fleck · fastest of 9 · top 5 within 6.9s+1.590s (+1.31%)2:03.334James French · fastest of 10 · top 5 within 1.4s+0.680s (+0.55%)158.6John McAleer+1.5 mph (+1.0%)2:26.911Andrew McDermid · fastest of 8 · top 5 within 3.4s+0.119s (+0.08%)2:28.471Andrew McDermid · fastest of 8 · top 5 within 2.4s-0.761s (-0.51%)151.0Andrew McDermid-0.6 mph (-0.4%)+25.137squal +24.398s120.4%qual 119.9%2:46.536Zachary Whitston · fastest of 37 · top 5 within 1.7s+2.435s (+1.48%)2:45.272Brian Farnham · fastest of 34 · top 5 within 1.3s-1.464s (-0.88%)117.4Rick Shields+0.2 mph (+0.1%)+41.938squal +44.023s134.0%qual 135.9%2:29.239Jon Brakke · fastest of 15 · top 5 within 5.2s+1.946s (+1.32%)2:27.869Jon Brakke · fastest of 15 · top 5 within 5.2s-0.887s (-0.60%)137.0Jon Brakke-3.8 mph (-2.7%)+24.535squal +26.726s119.9%qual 121.8%
41 rule changes (FA: 7, AS: 13, EP: 21)7 engine · 6 cars added · 6 induction · 6 weight · 3 aero · 1 suspension & brakes · 1 tyres & wheels · 8 wording · 3 other · AS Camaro 16+ Spec Line: 1LE front splitter kit permitted, belt tensioner and motor mount parts allowed, spark plug position defined. · AS class adds Pirelli P Zero Trofeo Track as permitted tyre option for competition. · AS class rear trailing arms no longer required to maintain stock length, only to locate rear axle. · AS Ford Mustang GT 4.6L 4-valve regains allowance, minimum weight 3200 lbs. · AS Ford Mustang Coupe GT 05-14 Gen3 Coyote minimum weight increases from 3100 to 3400 lbs. · HP Mini Cooper 02-06 compression ratio increases from 10.6 to 11.0:1. · FA sealed engine teardown: competitors no longer pay reassembly and resealing costs; stewards handle inspection per section 9.3.42. · 1996-2000 Honda Civic CX/DX/LX with D16Y7 engine newly classified in HP. · HP 1275 Midget/Sprite alternate intake manifold from MG-B now permitted; balance tube shortening and flange modification allowed. · HP Honda Civic DX/LX 92–95 wheels 13x7 to 15x7, weight 2420 to 2350 lbs. · AS GM LM7 5.3L must use full prep Holley carburetor as described in 9.1.6.D.c.1, not specifically 4776. · EP Honda S2000 gains permission to use Mugen hardtop P/N 0000-04-2312 or aftermarket equivalent. · FA Mazda 13B rotary permits one 48mm or 50mm dual-throat carburetor with 41.5mm venturi or fuel injection with 36mm SIR. · EP Mazda MX-5 94-97 front track widens to 1516 mm, rear to 1534 mm. · EP Triumph GT6 auto-type drivetrain choke size increases from 44mm to 45mm. · AS EFI engine build sheets add dry sump, header, camshaft, and timing chain tensioner options for LS, LT1, Ford, and Mopar engines. · AS LT1 Camaro engine build sheet added with full specs; LT1 weight 3200 lbs, GTO tire to 275, Mustang weight to 3525 lbs, oil catch tanks now required. · AS Spec Lines reorganized for 2026; detailed chassis, engine, weight, wheelbase, tire and brake specifications moved to main rules and engine build sheets. · AS GM LM7 5.3L gains Edelbrock 71187 intake manifold, MSD 6014 ignition box, Holly 4776 carb option under full prep spec line. · Pro Formula Mazda allows lower intake manifold unrestricted, throttle body increased to 80mm maximum. · AS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm. · EP BMW 325i/is E30 fuel injection throttle body specified as 60mm diameter. · FA MZR may use Noor P/N 0088-8-00 intake with AT Power runners; aluminum spacer minimum length 2.200 inches required. · FA Formula 1000 motorcycle-based 4-cycle engine loses maximum compression ratio 14.5:1 limit; current rules apply. · FA Formula 1000 allows carbon fiber external panels, forward-facing gaps, raises undertray to 125mm, allows eight 75×125mm rub blocks, widens diffuser to 110cm with 75mm radius transitions. · AS Ford Mustang GT 94-04 Restricted Prep Engine now permits Ford Motorsport M-6250-F303 camshaft. · EP Triumph TR2–TR4A may use 5-speed gearbox without overdrive; Weber carburetors and weight reference deleted. · EP BMW Z3 2.5L and other models get smaller restrictors, 50mm to 55mm, and Z3 2.5L weight rises 50 to 78 lbs. · AS Cadillac CTS-V 04-07 Restricted Prep minimum weight drops to 3400 lbs. · EP Nissan 280Z minimum weight lowered to 2400 lbs, 2460 lbs with *, 2520 lbs with **. · EP Mazda MX-5 1.8L 90-97 minimum weight reduced to 2125 lbs. · HP Spec Lines Austin-Healey Sprite/Midget 1098cc minimum weight drops to 1550 lbs. · HP Volvo 142 P-1800 engine gains compression ratio limit 12.0:1 and valve lift limit .425 inch. · HP Mini DOHC 1.6 valve lift limit drops to .390" from .450". · FP and HP Volkswagen Rabbit descriptions updated to clarify Cabriolet body style inclusion. · EP, FP, HP: rear drum-to-disc brake conversion clarified; rotors solid, diameter limited to largest front rotor permitted. · EP Ford Mustang 94-98 fuel injected throttle body inside diameter set to 60. · FA class adds USF Pro 2000 car as permitted model. · HP Plymouth Arrow gains 4 or 5 speed transmission option specification. · Appendix G.2.3 clarifies rim width and diameter are absolute maximums; wording corrected from 'is' to 'are'. · EP, FP, HP throttle body inside dimensions and butterfly now allow +/-.25mm tolerance from stock.showhide
  • AS 2016+ Camaro Spec Line Full Prep #39646otheraddedAS Camaro 16+ Spec Line: 1LE front splitter kit permitted, belt tensioner and motor mount parts allowed, spark plug position defined.
  • AS Consideration of Pirelli P Zero Trofeo Track for AS Competition #40495tyres & wheelsadded · tyres & wheelsAS class adds Pirelli P Zero Trofeo Track as permitted tyre option for competition.
  • AS Change in 9.1.6.D.4.d.5 in Suspension Mounting Points #40094suspension & brakesfaster · suspension & brakesAS class rear trailing arms no longer required to maintain stock length, only to locate rear axle.
  • AS Re-Add 4.6L 4v 96-04 Mustang Cobra #40239cars addedaddedAS Ford Mustang GT 4.6L 4-valve regains allowance, minimum weight 3200 lbs.
  • AS Errors and Omissions #40532weightslower · weightAS Ford Mustang Coupe GT 05-14 Gen3 Coyote minimum weight increases from 3100 to 3400 lbs.
  • EP Mini Cooper Compression Ratio #40517enginefaster · engineHP Mini Cooper 02-06 compression ratio increases from 10.6 to 11.0:1.
  • FA Update sealed engine teardown section #40621wordingaddedFA sealed engine teardown: competitors no longer pay reassembly and resealing costs; stewards handle inspection per section 9.3.42.
  • EP 1996-2000 Honda Civic (CX, DX, VP, LX) with Engine Code D16Y7 #40322cars addedadded1996-2000 Honda Civic CX/DX/LX with D16Y7 engine newly classified in HP.
  • EP 1275 Midget/Sprit Alternate intake manifold E/O #40370inductionadded · inductionHP 1275 Midget/Sprite alternate intake manifold from MG-B now permitted; balance tube shortening and flange modification allowed.
  • EP HP Honda Civic (92-95) #40464weight -70 lbsfaster · weightHP Honda Civic DX/LX 92–95 wheels 13x7 to 15x7, weight 2420 to 2350 lbs.
  • AS Clarification for LM7 Holley Carburetor #40167wordingwordingAS GM LM7 5.3L must use full prep Holley carburetor as described in 9.1.6.D.c.1, not specifically 4776.
  • EP Honda S2000 Hardtop #40138aeroadded · aeroEP Honda S2000 gains permission to use Mugen hardtop P/N 0000-04-2312 or aftermarket equivalent.
  • FA Motor Classification #40175cars addedaddedFA Mazda 13B rotary permits one 48mm or 50mm dual-throat carburetor with 41.5mm venturi or fuel injection with 36mm SIR.
  • EP Miata track width - errors and omissions #39976aerofaster · aeroEP Mazda MX-5 94-97 front track widens to 1516 mm, rear to 1534 mm.
  • EP Triumph GT6 Spec Change. #40098inductionfaster · inductionEP Triumph GT6 auto-type drivetrain choke size increases from 44mm to 45mm.
  • AS Header Information Update for EFI Engine Build Sheets #39886engineadded · engineAS EFI engine build sheets add dry sump, header, camshaft, and timing chain tensioner options for LS, LT1, Ford, and Mopar engines.
  • AS Errors and Omissions #39933otherfasterAS LT1 Camaro engine build sheet added with full specs; LT1 weight 3200 lbs, GTO tire to 275, Mustang weight to 3525 lbs, oil catch tanks now required.
  • AS Re-Organization of AS Spec lines for 2026 #39887wordingwordingAS Spec Lines reorganized for 2026; detailed chassis, engine, weight, wheelbase, tire and brake specifications moved to main rules and engine build sheets.
  • AS Edelbrock manifold (& timing kit) to Chevy LS Spec Lines Request #39055cars addedaddedAS GM LM7 5.3L gains Edelbrock 71187 intake manifold, MSD 6014 ignition box, Holly 4776 carb option under full prep spec line.
  • FA Pro Mazda Classification and Performance Enhancement Proposal #39411enginefaster · enginePro Formula Mazda allows lower intake manifold unrestricted, throttle body increased to 80mm maximum.
  • AS Restrictor Plate Change for Gen 2 Ford Coyote Engine #39501inductionslower · inductionAS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm.
  • EP Request to Update E30 BMW Throttle Body Diameter Verbiage #39363wordingwordingEP BMW 325i/is E30 fuel injection throttle body specified as 60mm diameter.
  • FA Alternate Intake Manifold for MZR #38223inductionadded · inductionFA MZR may use Noor P/N 0088-8-00 intake with AT Power runners; aluminum spacer minimum length 2.200 inches required.
  • FA Engine Compression Rule Change Request #39302enginefaster · engineFA Formula 1000 motorcycle-based 4-cycle engine loses maximum compression ratio 14.5:1 limit; current rules apply.
  • FA Change Formula 1000 allowances #39608aerofaster · aeroFA Formula 1000 allows carbon fiber external panels, forward-facing gaps, raises undertray to 125mm, allows eight 75×125mm rub blocks, widens diffuser to 110cm with 75mm radius transitions.
  • AS 1994 Mustang Spec Line Request #39104engineadded · engineAS Ford Mustang GT 94-04 Restricted Prep Engine now permits Ford Motorsport M-6250-F303 camshaft.
  • EP TR2 Notes E&O #39180wordingwordingEP Triumph TR2–TR4A may use 5-speed gearbox without overdrive; Weber carburetors and weight reference deleted.
  • EP Balance of Power #39187induction +50 lbsslower · inductionEP BMW Z3 2.5L and other models get smaller restrictors, 50mm to 55mm, and Z3 2.5L weight rises 50 to 78 lbs.
  • AS Cadillac CTS-V BOP Weight Change #38640weight -50 lbsfaster · weightAS Cadillac CTS-V 04-07 Restricted Prep minimum weight drops to 3400 lbs.
  • EP Please Lower Weight of 280Z #38871weight -160 lbsfaster · weightEP Nissan 280Z minimum weight lowered to 2400 lbs, 2460 lbs with *, 2520 lbs with **.
  • EP Miata Weight Adjustment Follow Up #38949weight -25 lbsfaster · weightEP Mazda MX-5 1.8L 90-97 minimum weight reduced to 2125 lbs.
  • EP Weight Break for 1098 Midget / Sprite #38970weight -80 lbsfaster · weightHP Spec Lines Austin-Healey Sprite/Midget 1098cc minimum weight drops to 1550 lbs.
  • EP HP Volvo 142 spec omission #38994engineslower · engineHP Volvo 142 P-1800 engine gains compression ratio limit 12.0:1 and valve lift limit .425 inch.
  • EP HP Mini DOHC 1.6 #38996engineslower · engineHP Mini DOHC 1.6 valve lift limit drops to .390" from .450".
  • EP Add to Rabbit description #39019wordingwordingFP and HP Volkswagen Rabbit descriptions updated to clarify Cabriolet body style inclusion.
  • EP Clean-up 9.1.5.E.7e #39025otherotherEP, FP, HP: rear drum-to-disc brake conversion clarified; rotors solid, diameter limited to largest front rotor permitted.
  • EP Add TB size to Ford Mustang (94-98) Spec Line #39130inductionadded · inductionEP Ford Mustang 94-98 fuel injected throttle body inside diameter set to 60.
  • FA Re-Consider USF Pro 2000 Car for Formula Atlantic Class #38783cars addedaddedFA class adds USF Pro 2000 car as permitted model.
  • EP HP Plymouth Arrow spec omission #38995cars addedaddedHP Plymouth Arrow gains 4 or 5 speed transmission option specification.
  • EP Add Wheel Diameter to Appendix G #39008wordingwordingAppendix G.2.3 clarifies rim width and diameter are absolute maximums; wording corrected from 'is' to 'are'.
  • EP Add TB ID tolerance to general Prod rules #39009wordingaddedEP, FP, HP throttle body inside dimensions and butterfly now allow +/-.25mm tolerance from stock.
Road America Runoffs 20252025-09-292:00.923Hans Peter · fastest of 12 · top 5 within 2.4s-0.637s (-0.52%)2:02.654Hans Peter · fastest of 11 · top 5 within 3.1s+0.864s (+0.71%)157.0Shane Kennett-3.0 mph (-1.9%)2:26.792Andrew McDermid · fastest of 11 · top 5 within 3.9s+0.214s (+0.15%)2:29.232Gregory Eaton · fastest of 10 · top 5 within 4.0s+2.803s (+1.91%)151.5Andrew McDermid+1.9 mph (+1.3%)+26.578squal +25.869s121.7%qual 121.4%2:44.101Andrew Abbott · fastest of 34 · top 5 within 1.3s+1.458s (+0.90%)2:46.736Zachary Whitston · fastest of 29 · top 5 within 0.6s+1.902s (+1.15%)117.2Zachary Whitston+0.7 mph (+0.6%)+44.082squal +43.178s135.9%qual 135.7%2:27.293Jon Brakke · fastest of 21 · top 5 within 2.1s+0.490s (+0.33%)2:28.756Tyler Ladd · fastest of 19 · top 5 within 1.9s+0.887s (+0.60%)140.8Jon Brakke+0.1 mph (+0.1%)+26.102squal +26.370s121.3%qual 121.8%
28 rule changes (FA: 3, AS: 11, EP: 14)7 weight · 5 induction · 4 engine · 3 cars added · 1 tyres & wheels · 5 wording · 3 other · AS Ford Mustang GT 5.0 2018- minimum weight reduced to 3525 lbs. · EP BMW Z4 03-05 gains 52mm flat plate intake restrictor. · EP Fiat 124 Spider Competition 1600 and 2000 minimum weight drops 50 lbs to 2000; carburetors now allow 36mm chokes instead of 34mm. · FA Ligier JS F3 front tires change to Hoosier 240/580R13 MS, rear to 300/590R13 MS. · AS Ford Mustang GT 05-14 Restricted Prep Engine gains additional gear ratio option: 3.66, 2.43, 1.69, 1.32, 1.00, .65. · HP Fiat X-1/9 and Bertone 1500 minimum weights reduced to 1740 lbs, 1784 lbs, 1827 lbs; 1300 models to 1600, 1640, 1680 lbs; additional 1300 and 1500 specs to 2010, 1900 lbs. · AS Ford Mustang GT 5.0L 15-17 flat plate restrictor reduces from 67mm to 64mm. · AS LS1/LS6 intakes added for 5.3L truck engine: part numbers 12561269 and 88894095. · AS Flotek head value seat cutting dimensions figure updated for consistency. · AS class notes cleaned: fuel cell and ECM specifications removed from multiple Camaro, Firebird, Challenger and Mustang variants. · Chevrolet Spark 16-22 classified in HP Pre at 1850 lbs base, 1896 lbs modified, 1943 lbs. · HP Ford Festiva 88-93 minimum weight lowered to 1600 lbs, competition weight to 1640, prepared weight to 1680; compression ratio raised to 11.0:1. · AS removes 'Any ECM maybe used' note from five Cadillac and Chevrolet/Pontiac V8 Restricted Prep models. · EP BMW Z3 2.5L, Z3 2.8L, 328i E36/E46, 325i E36/E46 intake restrictors reduced 4mm each, to 52–58mm. · EP, FP, HP may use any interior or exterior mirror meeting rule 9.3.36. · EP Honda S2000 1997cc minimum weight drops 75 lbs to 2375; 2157cc drops 60 lbs to 2450. · EP Mazda MX-5 Miata 99-05 minimum weight reduced to 2100 lbs, 2153 lbs with power, 2205 lbs modified. · FA Formula Renault 2.0 (10-17) spec notes clarified: engine sealed, manual compliance required, tyre choice unrestricted, no alterations except repairs. · EP BMW models now require flat plate intake restrictors: Z3 2.5L 52mm, Z3 2.8L 55mm, 328i E36 58mm, 328i/ci E46 58mm, 325i E46 56mm, 325i E36 56mm, 325is M-Technic 56mm. · FA adds Formula Regional European Championship Tatuus F.3 T-318 or FR-19 as spec line car in Table 2. · AS Ford Mustang and Cobra Coyote engine restrictor increases to 80mm from 67mm or 64mm. · AS Mustang GT 05-14 Restricted loses 300 lbs engine; 15-17 and 2018+ models lose 61mm and 60mm restrictors respectively. · AS class: multiple American muscle cars gain additional allowed gear ratio options across model years and prep levels. · AS LS-engine cars gain ECU freedom: CTS-V, Camaro, Firebird (70–02) and Camaro SS may use any ECM. · EP BMW 325i/is E30 84-91 weight reduced to 2150 lbs base, 2204 lbs with turbo, 2258 lbs supercharged. · EP Triumph GT6 switches to three Weber 40 DCOE carburetors with 28mm chokes, weight rises to 1990 lbs. · HP 1275 Spridget compression ratio raised to 12.0:1; 1098cc also raised to 12.0:1. · EP Miata 1.6L, 1.8L 90–97, and 94–97 track width corrected to 1516/1534 mm (59.7/60.4 in.) front and rear.showhide
  • AS RE: Previous Letter 37695 Update #38245weight -75 lbsfaster · weightAS Ford Mustang GT 5.0 2018- minimum weight reduced to 3525 lbs.
  • EP BMW Z4 update #38490inductionslower · inductionEP BMW Z4 03-05 gains 52mm flat plate intake restrictor.
  • EP EP Fiat 124 Spider Competition Adjustment Request #38498weight -50 lbsfaster · weightEP Fiat 124 Spider Competition 1600 and 2000 minimum weight drops 50 lbs to 2000; carburetors now allow 36mm chokes instead of 34mm.
  • FA Ligier JS F3 Tire Choice #38434tyres & wheelstyres & wheelsFA Ligier JS F3 front tires change to Hoosier 240/580R13 MS, rear to 300/590R13 MS.
  • AS Errors and Omissions #38234otheraddedAS Ford Mustang GT 05-14 Restricted Prep Engine gains additional gear ratio option: 3.66, 2.43, 1.69, 1.32, 1.00, .65.
  • EP Base Weight Adjustment for H-Production X1/9 Spec Lines #38255weight -50 lbsfaster · weightHP Fiat X-1/9 and Bertone 1500 minimum weights reduced to 1740 lbs, 1784 lbs, 1827 lbs; 1300 models to 1600, 1640, 1680 lbs; additional 1300 and 1500 specs to 2010, 1900 lbs.
  • AS Errors and Omission #38055inductionslower · inductionAS Ford Mustang GT 5.0L 15-17 flat plate restrictor reduces from 67mm to 64mm.
  • AS Request to Add LS1/LS6 Intakes for 5.3L Truck Engine EnO #38197cars addedaddedAS LS1/LS6 intakes added for 5.3L truck engine: part numbers 12561269 and 88894095.
  • AS Flotek Head Plunge Cut Inconsistencies #37502wordingwordingAS Flotek head value seat cutting dimensions figure updated for consistency.
  • AS Notes clean up #37693wordingwordingAS class notes cleaned: fuel cell and ECM specifications removed from multiple Camaro, Firebird, Challenger and Mustang variants.
  • EP Request for Classification of Chevrolet Spark #37755cars addedaddedChevrolet Spark 16-22 classified in HP Pre at 1850 lbs base, 1896 lbs modified, 1943 lbs.
  • EP Request to Lower Ford Festiva Minimum Weight to 1600 LBS #37939weight -100 lbsfaster · weightHP Ford Festiva 88-93 minimum weight lowered to 1600 lbs, competition weight to 1640, prepared weight to 1680; compression ratio raised to 11.0:1.
  • AS Race memo #37902wordingwordingAS removes 'Any ECM maybe used' note from five Cadillac and Chevrolet/Pontiac V8 Restricted Prep models.
  • EP Request Competition Adjustment to BMW Z3 2.5L #37120inductionslower · inductionEP BMW Z3 2.5L, Z3 2.8L, 328i E36/E46, 325i E36/E46 intake restrictors reduced 4mm each, to 52–58mm.
  • EP Interpretation of Production Rules on Mirrors #37235wordingaddedEP, FP, HP may use any interior or exterior mirror meeting rule 9.3.36.
  • EP Weight Reduction for Honda S2000 #37466weightfaster · weightEP Honda S2000 1997cc minimum weight drops 75 lbs to 2375; 2157cc drops 60 lbs to 2450.
  • EP Mazda 1999 Miata 1.8L #37488weight -50 lbsfaster · weightEP Mazda MX-5 Miata 99-05 minimum weight reduced to 2100 lbs, 2153 lbs with power, 2205 lbs modified.
  • FA Update Formula Renault 2.0 spec line notes #37853wordingwordingFA Formula Renault 2.0 (10-17) spec notes clarified: engine sealed, manual compliance required, tyre choice unrestricted, no alterations except repairs.
  • EP Effective date for Jan 2025 GCR updates #37654inductionslower · inductionEP BMW models now require flat plate intake restrictors: Z3 2.5L 52mm, Z3 2.8L 55mm, 328i E36 58mm, 328i/ci E46 58mm, 325i E46 56mm, 325i E36 56mm, 325is M-Technic 56mm.
  • FA Classify FR European Championship car as spec line car in Table 2 #37658cars addedaddedFA adds Formula Regional European Championship Tatuus F.3 T-318 or FR-19 as spec line car in Table 2.
  • AS Increase Coyote Engine Restrictor to 80mm #36177enginefaster · engineAS Ford Mustang and Cobra Coyote engine restrictor increases to 80mm from 67mm or 64mm.
  • AS Performance Pack for 2015+ Mustang #36867enginefaster · engineAS Mustang GT 05-14 Restricted loses 300 lbs engine; 15-17 and 2018+ models lose 61mm and 60mm restrictors respectively.
  • AS Gear Ratios #37131otheraddedAS class: multiple American muscle cars gain additional allowed gear ratio options across model years and prep levels.
  • AS ECU specs for LS engine #37208engineadded · engineAS LS-engine cars gain ECU freedom: CTS-V, Camaro, Firebird (70–02) and Camaro SS may use any ECM.
  • EP Request to Reduce Weight of BMW 325i/is E30 (84-91) Spec Line #37119weight -50 lbsfaster · weightEP BMW 325i/is E30 84-91 weight reduced to 2150 lbs base, 2204 lbs with turbo, 2258 lbs supercharged.
  • EP Triumph GT6 Adjustments #37112inductionfaster · inductionEP Triumph GT6 switches to three Weber 40 DCOE carburetors with 28mm chokes, weight rises to 1990 lbs.
  • EP 1275 HP Spridget Level 2 Only #36518enginefaster · engineHP 1275 Spridget compression ratio raised to 12.0:1; 1098cc also raised to 12.0:1.
  • EP NA Miata Track Width Correction #36902otherotherEP Miata 1.6L, 1.8L 90–97, and 94–97 track width corrected to 1516/1534 mm (59.7/60.4 in.) front and rear.
Road America Runoffs 20242024-10-012:01.560Hans Peter · fastest of 13 · top 5 within 2.0s-2.714s (-2.18%)2:01.790Dudley Fleck · fastest of 12 · top 5 within 3.3s-2.956s (-2.37%)160.0Brandon Schwarz+9.4 mph (+6.3%)2:26.578Gregory Eaton · fastest of 18 · top 5 within 2.6s-0.467s (-0.32%)2:26.429Gregory Eaton · fastest of 18 · top 5 within 2.5s-1.239s (-0.84%)149.6Gregory Eaton+0.4 mph (+0.3%)+24.639squal +25.018s120.2%qual 120.6%2:42.643Andrew Whitston · fastest of 27 · top 5 within 2.3s-1.351s (-0.82%)2:44.834Andrew Abbott · fastest of 27 · top 5 within 0.9s-0.982s (-0.59%)116.5Brian Farnham-0.7 mph (-0.6%)+43.044squal +41.083s135.3%qual 133.8%2:26.803Tyler Ladd · fastest of 16 · top 5 within 4.1s-0.519s (-0.35%)2:27.869Tyler Ladd · fastest of 16 · top 5 within 3.6s-1.178s (-0.79%)140.7Bill Miller-1.0 mph (-0.7%)+26.079squal +25.243s121.4%qual 120.8%
27 rule changes (AS: 11, FV: 2, EP: 14)8 cars added · 7 weight · 1 engine · 1 induction · 1 removed · 1 tyres & wheels · 4 wording · 4 other · FV ferrous rotor must not be cross-drilled; pad cleaning grooves limit unchanged at three per side. · AS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options. · HP Volkswagen Golf and Jetta 85-92 track correction: front 1537 mm (60.5 in.), rear 1529 mm (60.2 in.). · AS adds 2018-23 Ford Mustang GT 5.0L at 3600 lbs, 275 tire, 60mm restrictor, optional Brembo front brakes. · Nissan 300ZX 84–89 added to EP, 2550–2678 lbs, 2960 cc SOHC, fuel injection, 12.0:1 compression, 0.500" valve lift limit. · Mazda RX-7 92-97 added to EP Prep as Level 2 rotary 13B 6-port, 2200–2310 lbs, carb or fuel injection, 42 mm choke. · EP Mazda RX-8 (04-11) alternate spec line removed; single spec line retained. · AS Chevrolet Camaro 1LE (2016-) added with 3600 lbs minimum weight, 275 tires, 60mm restrictor, 345/338mm brakes. · AS Chevrolet/Pontiac Camaro & Firebird 82–92 5.7L LS1 classified: 3200 lbs, 13.1×1.27 disc brakes, 17 in max wheel, 65 mm restrictor, SLP intake lid permitted. · AS Chevrolet Camaro, Firebird, and Ford Mustang now permit Flo Tek cylinder heads in multiple generations. · AS Camaro, Firebird 93-02 and GTO 04-06 add approved LS1 connecting rod part numbers to Notes. · AS Cadillac CTS-V, Chevy Camaro SS V8, Dodge Challenger, Ford Mustang GT 5.0L, Pontiac GTO allowed 11" wheels until 3/1/25. · Chevrolet Camaro, Pontiac Firebird 70–81 Full Prep classified in AS at 3400–3600 lbs with 108.0 wheelbase, specific head castings, and suspension modifications permitted. · AS class adds fuel cell location notes to multiple Cadillac, Chevrolet, Dodge and Ford models: cells within 24 inches of standard tank. · Chevrolet Camaro 6th gen Full Prep added to AS class at 3400 lbs base or 3600 lbs with built engine. · AS class: Ford Mustang GT 05-14 Restricted prep added; Cadillac CTS-V 04-07 to 3450 lbs; Camaro/Firebird variants reconfigured with weight and notes changes; Dodge Challenger 08-20 restrictor 76mm to 80mm; Ford Mustang variants updated wei… · HP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve 83-88, Scirocco 1588. · HP Honda Civic 1.5 1988-91 minimum weight drops 70 lbs to 2175; also 2-speed and 3-speed minimums cut 72 and 73 lbs. · EP BMW Z3 2.5L minimum weight increased to 2500 lbs, 2563 lbs with power adder, 2625 lbs with two power adders. · EP Mazda MX-5 1.8L (90-97) minimum weight cut to 2150 lbs; (94-97) variants to 2000, 2050, 2100 lbs. · EP Triumph GT6 dual 1.75-inch carburetors weight rises to 1940 lbs; triple Weber 40 DCOE option added at 1990 lbs. · EP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm. · EP Triumph TR8 dry sump allowance moved from Carburetor line to Notes. · EP Porsche 944/924S 2.5L and 2.7L minimum weights corrected: 2479cc to 2306–2363 lbs, 2681cc to 2358–2415 lbs. · EP Porsche 944/924S combines 2.5L and 2.7L variants (83-89), raises weight to 2250–2415 lbs, allows 2681cc displacement. · EP Triumph GT6 minimum weight drops to 1800 lbs. · FV front wheel bearings wording clarified; specification unchanged.showhide
  • FV Disc Brakes #36822wordingwordingFV ferrous rotor must not be cross-drilled; pad cleaning grooves limit unchanged at three per side.
  • AS Mustang transmission ratios #36662otheraddedAS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options.
  • EP Errant entry in HP production line item #36231wordingwordingHP Volkswagen Golf and Jetta 85-92 track correction: front 1537 mm (60.5 in.), rear 1529 mm (60.2 in.).
  • AS Request for Classification of 2018-2023 mustang In #35764cars addedaddedAS adds 2018-23 Ford Mustang GT 5.0L at 3600 lbs, 275 tire, 60mm restrictor, optional Brembo front brakes.
  • EP NIssan 300ZX Z31 to EP #35830cars addedaddedNissan 300ZX 84–89 added to EP, 2550–2678 lbs, 2960 cc SOHC, fuel injection, 12.0:1 compression, 0.500" valve lift limit.
  • EP RX7 1993 and Up Request In EP Spec Lines, classify #36031cars addedaddedMazda RX-7 92-97 added to EP Prep as Level 2 rotary 13B 6-port, 2200–2310 lbs, carb or fuel injection, 42 mm choke.
  • EP Clean-up Multiple EP RX-8 Spec Lines In EP #36156cars addedremoved · cars addedEP Mazda RX-8 (04-11) alternate spec line removed; single spec line retained.
  • AS 6th gen Camaro limited prep #35733cars addedaddedAS Chevrolet Camaro 1LE (2016-) added with 3600 lbs minimum weight, 275 tires, 60mm restrictor, 345/338mm brakes.
  • AS Chevrolet/Pontiac Camaro & Firebird (82-92) 5.7L V8 LS1 Alum BLK #35825cars addedaddedAS Chevrolet/Pontiac Camaro & Firebird 82–92 5.7L LS1 classified: 3200 lbs, 13.1×1.27 disc brakes, 17 in max wheel, 65 mm restrictor, SLP intake lid permitted.
  • AS Full Prep Head #35891engineadded · engineAS Chevrolet Camaro, Firebird, and Ford Mustang now permit Flo Tek cylinder heads in multiple generations.
  • AS Restricted Prep Aftermarket Parts Request #35682otheraddedAS Camaro, Firebird 93-02 and GTO 04-06 add approved LS1 connecting rod part numbers to Notes.
  • AS Allowance of 11 #35824tyres & wheelsfaster · tyres & wheelsAS Cadillac CTS-V, Chevy Camaro SS V8, Dodge Challenger, Ford Mustang GT 5.0L, Pontiac GTO allowed 11" wheels until 3/1/25.
  • AS Request to Classify 1970-1981 Camaro and Firebird in AS #33659cars addedaddedChevrolet Camaro, Pontiac Firebird 70–81 Full Prep classified in AS at 3400–3600 lbs with 108.0 wheelbase, specific head castings, and suspension modifications permitted.
  • AS Fuel Cell 12 #34194otheraddedAS class adds fuel cell location notes to multiple Cadillac, Chevrolet, Dodge and Ford models: cells within 24 inches of standard tank.
  • AS Please Classify the 6th Gen Into AS. #35448cars addedaddedChevrolet Camaro 6th gen Full Prep added to AS class at 3400 lbs base or 3600 lbs with built engine.
  • AS spec lines #35713otherunclearAS class: Ford Mustang GT 05-14 Restricted prep added; Cadillac CTS-V 04-07 to 3450 lbs; Camaro/Firebird variants reconfigured with weight and notes changes; Dodge Challenger 08-20 restrictor 76mm to 80mm; Ford Mustang variants updated wei…
  • EP GCR Correction - Redundant HP Spec Lines #35623removedremovedHP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve 83-88, Scirocco 1588.
  • EP Update 1988-1991 Civic to Match 1988-1991 CRX #35399weightfaster · weightHP Honda Civic 1.5 1988-91 minimum weight drops 70 lbs to 2175; also 2-speed and 3-speed minimums cut 72 and 73 lbs.
  • EP Request to Review Z3 2.5 Spec Line #35073weight +50 lbsslower · weightEP BMW Z3 2.5L minimum weight increased to 2500 lbs, 2563 lbs with power adder, 2625 lbs with two power adders.
  • EP Miata Alternate Head #35253weight -50 lbsfaster · weightEP Mazda MX-5 1.8L (90-97) minimum weight cut to 2150 lbs; (94-97) variants to 2000, 2050, 2100 lbs.
  • EP Triumph GT6 Adjustments #35255weightslower · weightEP Triumph GT6 dual 1.75-inch carburetors weight rises to 1940 lbs; triple Weber 40 DCOE option added at 1990 lbs.
  • EP Honda S2000 throttle body #35272inductionfaster · inductionEP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm.
  • EP Correction within Triumph TR8 Spec Line #35315wordingwordingEP Triumph TR8 dry sump allowance moved from Carburetor line to Notes.
  • EP Correction to EP 924S/944 Spec Line #35317weightweightEP Porsche 944/924S 2.5L and 2.7L minimum weights corrected: 2479cc to 2306–2363 lbs, 2681cc to 2358–2415 lbs.
  • EP Porsche 944/924S Rule Change Request #35002weightslower · weightEP Porsche 944/924S combines 2.5L and 2.7L variants (83-89), raises weight to 2250–2415 lbs, allows 2681cc displacement.
  • EP Triumph GT6 Adjustments #35054weight -30 lbsfaster · weightEP Triumph GT6 minimum weight drops to 1800 lbs.
  • FV FV Wheel Bearing Clarification #35150wordingwordingFV front wheel bearings wording clarified; specification unchanged.
Virginia International Raceway Runoffs 20232023-09-232:03.082Daniel Richardson · fastest of 11 · top 5 within 2.2s+0.920s (+0.75%)2:04.120Gregory Eaton · fastest of 9 · top 5 within 3.0s-0.458s (-0.37%)154.6James Jost+3.7 mph (+2.5%)2:15.639Andrew Whitston · fastest of 27 · top 5 within 1.4s+0.523s (+0.39%)2:16.611Andrew Abbott · fastest of 23 · top 5 within 1.6s-1.482s (-1.07%)115.6Brian Farnham-0.2 mph (-0.2%)2:03.215John Hainsworth · fastest of 24 · top 5 within 4.3s+0.889s (+0.73%)2:04.050Greg Ira · fastest of 22 · top 5 within 5.3s-26.805s (-17.77%)144.6Greg Ira+3.1 mph (+2.2%)
24 rule changes (FA: 7, AS: 4, EP: 13)3 cars added · 2 engine · 2 induction · 2 tyres & wheels · 2 weight · 1 removed · 1 suspension & brakes · 7 wording · 4 other · EP Triumph TR8 78-81 removes allowance for alternate front hubs of same external dimensions and weight. · EP Triumph GT6 carburetor type changes from SU or Stromberg to Auto-type, quantity two 1.5 inch. · EP Triumph GT6 Brakes Alt. now permits TR-6 standard or alternate calipers and discs. · AS crate motor part number specification clarified; both CT400 P/N-19370604 and 19370604 engine assemblies permitted for GM vehicles. · AS Ford Mustang GT 5.0L (15-17) Restricted maximum wheel diameter increases to 19.0 inches. · AS Dodge Challenger 5.7L/6.1L/6.4L V8 allows alternate front upper control arms; SPC-66045 spec part removed. · AS Dodge Challenger 5.7L/6.1L/6.4L V8 now allows alternate front brake calipers with adaptor brackets for component compatibility. · FP and HP Sprite and Spitfire 1500 intake valve size corrected to 36.6 mm, removing prior decimal specifications. · EP Porsche 914-6 2.0L intake valve increased to 2.0 mm, exhaust valve corrected to 38.0 mm. · FA Pro Formula Mazda front wheel width minimum raised to 10 inches, rear to 14 minimum and 15 maximum. · FA Pro Formula Mazda maximum bodywork width behind front wheels increases to 51.97 inches, from 51.17 inches. · FA MSR Formula Mazda FMzR added to Table 2 classification. · EP BMW Z3 2.5L flat plate intake restrictor reduced from 58mm to 56mm, both throttle bodies. · EP 79-85 RX-7 brake hub and rotor spec removed; 13B rotor housing and housing options now permitted. · EP Nissan 280Z carburetor option clarified: Hitachi-SU 1bbl 46mm throttle bores or fuel injection permitted. · EP Mazda RX-2, RX-3, RX-3SP, RX-7 12A gain 2 bbl fuel injected throttle body option; RX-7 13B gains fuel injected throttle body and stock fuel injection. · EP Mazda RX-2, RX-3, RX-3SP lose 50–52 lbs; RX-4 loses 50–52 lbs across all specs. · EP Triumph TR8 78-81 now allowed dry sump installation. · EP, FP, HP port matching limited to 1 inch depth from mating surface. · EP Prep adds Nissan 280ZX (79-83) at 2425–2546 lbs with 2760cc SOHC six, fuel injection, 12.0:1 compression limit, 0.500" valve lift limit. · Unable to complete: rule text does not show the spec line to be added to FA Table 1 for BDA displacement. · Formula Renault 2.0 (10-17) reclassified from FX to FA spec line; minimum weight reduced 1300 to 1280 lbs, restrictor removed. · FA Swift 016 2.3L Mazda Duratec restrictor increases to 32mm, minimum weight drops to 1420 lbs. · Pro Formula Mazda allows street or bridge port, unmodified OEM lower intake manifold, 70mm throttle body, wing height to 99cm, bodywork width to 132cm.showhide
  • EP Hub Note Clean Up In EP TR8 Spec Line #34649removedremovedEP Triumph TR8 78-81 removes allowance for alternate front hubs of same external dimensions and weight.
  • EP Triumph GT6 Adjustments #34662engineengineEP Triumph GT6 carburetor type changes from SU or Stromberg to Auto-type, quantity two 1.5 inch.
  • EP Triumph GT6 Adjustments: Brakes #34663suspension & brakesadded · suspension & brakesEP Triumph GT6 Brakes Alt. now permits TR-6 standard or alternate calipers and discs.
  • AS Crate Motor Part Numbers #32944wordingwordingAS crate motor part number specification clarified; both CT400 P/N-19370604 and 19370604 engine assemblies permitted for GM vehicles.
  • AS Request wheel size change #33007tyres & wheelsfaster · tyres & wheelsAS Ford Mustang GT 5.0L (15-17) Restricted maximum wheel diameter increases to 19.0 inches.
  • AS Alternative Upper Front Control Arms for Dodge Challenger #33352wordingwordingAS Dodge Challenger 5.7L/6.1L/6.4L V8 allows alternate front upper control arms; SPC-66045 spec part removed.
  • AS Front Brake Caliper Adapters for Dodge Challenger #33353otherotherAS Dodge Challenger 5.7L/6.1L/6.4L V8 now allows alternate front brake calipers with adaptor brackets for component compatibility.
  • EP Correct Intake Valve Size on 1500cc Midget/Spitfire #34419wordingwordingFP and HP Sprite and Spitfire 1500 intake valve size corrected to 36.6 mm, removing prior decimal specifications.
  • EP 914-6 Valve Size Correction #34185enginefaster · engineEP Porsche 914-6 2.0L intake valve increased to 2.0 mm, exhaust valve corrected to 38.0 mm.
  • FA Simplify Pro Formula Mazda wheel allowance #34190tyres & wheelsslower · tyres & wheelsFA Pro Formula Mazda front wheel width minimum raised to 10 inches, rear to 14 minimum and 15 maximum.
  • FA E&O - Correct Pro Formula Mazda spec line dimensional equivalent #34085wordingwordingFA Pro Formula Mazda maximum bodywork width behind front wheels increases to 51.97 inches, from 51.17 inches.
  • FA Add new spec line for MSR Formula Mazda FMzR to Table 2 #34139cars addedaddedFA MSR Formula Mazda FMzR added to Table 2 classification.
  • EP Investigate Parity of Z3 #33343inductionslower · inductionEP BMW Z3 2.5L flat plate intake restrictor reduced from 58mm to 56mm, both throttle bodies.
  • EP Revise 79-85 RX7 Brake Spec Line Allowance #33293otherotherEP 79-85 RX-7 brake hub and rotor spec removed; 13B rotor housing and housing options now permitted.
  • EP Request alternate carburetors for EP 280z #33405wordingwordingEP Nissan 280Z carburetor option clarified: Hitachi-SU 1bbl 46mm throttle bores or fuel injection permitted.
  • EP Fuel Injection 12a Mazda RX3 #33434cars addedaddedEP Mazda RX-2, RX-3, RX-3SP, RX-7 12A gain 2 bbl fuel injected throttle body option; RX-7 13B gains fuel injected throttle body and stock fuel injection.
  • EP Mazda RX3 - Weight Reduction #33436weight -50 lbsfaster · weightEP Mazda RX-2, RX-3, RX-3SP lose 50–52 lbs; RX-4 loses 50–52 lbs across all specs.
  • EP Request TR8 Dry Sump Allowance #33460otheraddedEP Triumph TR8 78-81 now allowed dry sump installation.
  • EP Review Limited Prep Port Matching Rules #33600wordingwordingEP, FP, HP port matching limited to 1 inch depth from mating surface.
  • EP 280ZX Classification Request #33611cars addedaddedEP Prep adds Nissan 280ZX (79-83) at 2425–2546 lbs with 2760cc SOHC six, fuel injection, 12.0:1 compression limit, 0.500" valve lift limit.
  • FA BDA Displacement #33431otherunclearUnable to complete: rule text does not show the spec line to be added to FA Table 1 for BDA displacement.
  • FA Reclassify 2010-2017 Formula Renault 2.0 as a spec line car in FA #33395weightfaster · weightFormula Renault 2.0 (10-17) reclassified from FX to FA spec line; minimum weight reduced 1300 to 1280 lbs, restrictor removed.
  • FA Change Swift 016 2.3L restrictor size and minimum weight #33472induction -30 lbsfaster · inductionFA Swift 016 2.3L Mazda Duratec restrictor increases to 32mm, minimum weight drops to 1420 lbs.
  • FA Pro Formula Mazda Dimension E&O #33160wordingwordingPro Formula Mazda allows street or bridge port, unmodified OEM lower intake manifold, 70mm throttle body, wing height to 99cm, bodywork width to 132cm.
Virginia International Raceway Runoffs 20222022-09-241:44.703Chip Romer · fastest of 7 · top 5 within 4.0s+3.158s (+3.11%)1:48.507Alex Mayer · fastest of 4 · top 4 within 4.2s+5.400s (+5.24%)154.6Austin Hill-1.4 mph (-0.9%)2:02.162Kurt Rezzetano · fastest of 13 · top 5 within 2.3s-0.776s (-0.63%)2:04.578Gregory Eaton · fastest of 11 · top 5 within 2.9s+0.678s (+0.55%)150.9James Jost-3.0 mph (-2.0%)+16.071squal +17.459s114.8%qual 116.7%2:15.116Brian Farnham · fastest of 29 · top 5 within 1.1s-0.596s (-0.44%)2:18.093Andrew Whitston · fastest of 28 · top 5 within 1.2s-0.196s (-0.14%)115.8Jonathan Weisheit+1.1 mph (+0.9%)+29.586squal +30.413s127.3%qual 129.0%2:02.326Jesse Prather · fastest of 17 · top 5 within 3.2s+1.339s (+1.11%)2:30.855Jesse Prather · fastest of 15 · top 5 within 2.5s+29.224s (+24.03%)141.5Jesse Prather-6.0 mph (-4.1%)+42.348squal +17.623s139.0%qual 116.8%
41 rule changes (FA: 7, AS: 9, FV: 4, EP: 21)8 engine · 6 cars added · 5 weight · 3 induction · 2 tyres & wheels · 1 aero · 1 suspension & brakes · 13 wording · 2 other · AS adds Hoosier W2 wet tyre option alongside R7, R6, WET/H20. · AS Dodge Challenger 08-20 gains two transmission ratio options: 2.97–0.50 or 2.26–0.63. · Volkswagen New Beetle 2.5L 5-cyl DOHC classified in EP at 2400–2520 lbs with fuel injection. · EP Mazda RX-7 12A/13B and 13B now permit 2 bbl fuel injected throttle body with 42mm chokes on dual-y manifold. · EP VW Corrado 92-95 stroke corrected to 90.3 mm and displacement to 2792 cc. · AS Cadillac CTS-V 6.0L V8 Restricted Prep removes 295 tire size 50 lb penalty. · EP Subaru BRZ title updated to include model years 13–20; Toyota 86/Scion FR-S title likewise updated to 13–20. · EP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with 150 lbs penalty. · BMW 128i (08-13) classified in EP at 2700 lbs minimum with 2996 cc engine, stock throttle body, 11.0:1 compression and 0.400" valve lift limits. · EP, FP, HP open cars now allow carbon fiber hardtops if they retain OEM exterior profiles. · FA Ligier JS F3 must comply with FR Americas rules; competitors need current FR Americas Championship Sporting Regulations, Onroak manual, and HPD engine specs. · FA sealed engines now require full inspection by stewards; competitor pays all reassembly and resealing costs. · FA Formula Lites FL15 and FR Americas Ligier JS F3 engine sealing requirements clarified with regulatory references. · EP Mazda RX-8 13B carburetor option replaced with fuel-injected throttle body or stock fuel injection. · EP, FP, HP Production clarify idle control valve options: stock original allowed, removable with blocked ports, or mechanical replaced with electronic stock type. · FA: transverse gearbox shafts prohibited except final drive and motorcycle gearbox in Formula 1000. · FA Swift 016 2.5 liter aero spec now references 2.3 liter notes instead of N notes. · EP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate. · Ford Mustang 94-98 weight reduced to 2550/2614/2678 lbs; 99-03 3.8L classified EP at 2700/2768/2835 lbs. · EP, FP, HP Improved Touring cars may use any DOT-approved tyre as defined by 9.3.45. · FA Pro Formula Mazda now allows street port or bridge port; porting was previously not permitted. · FV connecting rod options expanded to include BrianCrower part BC6417 and Newland Group part 4M113077. · FV connecting rods minimum weight 425.0 grams, center-to-center length 130 +0.10/-0.25 mm; Crower, BrianCrower, Newland Group parts allowed if meeting specs. · EP, FP, HP: stock/original idle control devices permitted unmodified or completely removed with openings blocked. · EP Porsche 968 (92-95) now allowed to run dry sump. · EP 1979-1985 Mazda RX-7 12A and 13B minimum weights cut 50–53 lbs across all spec lines. · FA adds Honda K20Z3 2.0L at 1350 lbs and Mazda MZR 2.0L at 1300 lbs; removes 4A-GE 1.8L and MZR 2.0L from Table 2; raises 1615cc baseline to 1250 lbs. · SMG Long Tube Headers: Borla PN 17237 discontinued, approved alternatives American Racing MT3-05134300LSNC or Kooks PN 11312000. · AS Mercury Capri 79-86 removed as separate spec line, merged into Ford Mustang 79-93 spec line. · AS Spec Mustang SMG Restricted Prep removes 3.73 gear ratio and 355/300 brake disc sizes. · AS Camaro, Firebird, Mustang full prep engines: alternate GM and Ford Performance cylinder heads permitted regionally with Allstar restrictor ALL26180. · EP Porsche 968 intake valve size changes to 39.0 mm, 1.54 mm seat width. · EP, FP, HP front-wheel-drive cars may alter body and subframes to install alternate axle shaft, matching RWD freedom. · EP BMW Z3 2.5L adds alternate throttle body option with Turner adapter and permits head casting 1738400. · FV Crower connecting rods SP93280B and BC6417 allowed as direct replacement, must meet OEM minimum weight. · EP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; compression ratio 12.0:1 max, valve lift 0.500" max, dry sump allowed. · Toyota Corolla GTS RWD (84-87) and FX16 FWD (87-88) added to HP; old Corolla (84-87) removed. · FV allows Crower SP93280B and Brian Crower Racing Rods connecting rods as direct replacements, matching OEM minimum weight. · AS Chevrolet/Pontiac Camaro & Firebird 93-02 gains BMR AA004 or UMI 2310 adjustable front upper control arms. · AS Pontiac GTO 04-06 Restricted Prep minimum weight rises: LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tires. · Toyota MR-2 1.6L 85-89 HP track width corrected to 15×47 / 15×47 inches; stock track baseline now 103% plus 2.5 inches.showhide
  • AS Request to add Hoosier W2 #33031tyres & wheelsadded · tyres & wheelsAS adds Hoosier W2 wet tyre option alongside R7, R6, WET/H20.
  • AS correction of Dodge Challenger specification line #33151cars addedaddedAS Dodge Challenger 08-20 gains two transmission ratio options: 2.97–0.50 or 2.26–0.63.
  • EP Request to classify VW New Beetle 2.5L in EP #32725cars addedaddedVolkswagen New Beetle 2.5L 5-cyl DOHC classified in EP at 2400–2520 lbs with fuel injection.
  • EP Request Rotary Injection on Dual Y manifold #32775inductionadded · inductionEP Mazda RX-7 12A/13B and 13B now permit 2 bbl fuel injected throttle body with 42mm chokes on dual-y manifold.
  • EP Request for Corrado Stroke & Displacement Correction #32985wordingwordingEP VW Corrado 92-95 stroke corrected to 90.3 mm and displacement to 2792 cc.
  • AS Request CTS-V Spec Line Error Correction #30242weightfaster · weightAS Cadillac CTS-V 6.0L V8 Restricted Prep removes 295 tire size 50 lb penalty.
  • EP Subaru BRZ Model Years #32500wordingwordingEP Subaru BRZ title updated to include model years 13–20; Toyota 86/Scion FR-S title likewise updated to 13–20.
  • EP EP MX-5 Global Cup Car #32218weightweightEP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with 150 lbs penalty.
  • EP Please Class BMW 128i in EP #32370cars addedaddedBMW 128i (08-13) classified in EP at 2700 lbs minimum with 2996 cc engine, stock throttle body, 11.0:1 compression and 0.400" valve lift limits.
  • EP Inconsistency in Body Work Descriptions #32396aeroadded · aeroEP, FP, HP open cars now allow carbon fiber hardtops if they retain OEM exterior profiles.
  • FA Update FR Americas rulebook requirement #32491wordingwordingFA Ligier JS F3 must comply with FR Americas rules; competitors need current FR Americas Championship Sporting Regulations, Onroak manual, and HPD engine specs.
  • FA Clarify verification of sealed engine compliance #32522wordingwordingFA sealed engines now require full inspection by stewards; competitor pays all reassembly and resealing costs.
  • FA Clarify Formula Lites and FR Americas sealed engine requirement #32523wordingwordingFA Formula Lites FL15 and FR Americas Ligier JS F3 engine sealing requirements clarified with regulatory references.
  • EP Mazda RX8 with 13b Rotary #32170engineengineEP Mazda RX-8 13B carburetor option replaced with fuel-injected throttle body or stock fuel injection.
  • EP Request Idle control valve clarification #32178wordingwordingEP, FP, HP Production clarify idle control valve options: stock original allowed, removable with blocked ports, or mechanical replaced with electronic stock type.
  • FA E&O FA Transmission section #32251wordingwordingFA: transverse gearbox shafts prohibited except final drive and motorcycle gearbox in Formula 1000.
  • FA E&O Swift 016 2.5 liter Aero column #32363wordingwordingFA Swift 016 2.5 liter aero spec now references 2.3 liter notes instead of N notes.
  • EP EP Adjustments #31858inductionslower · inductionEP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate.
  • EP 1999 3.8L Ford Mustang to EP? #31635weightfaster · weightFord Mustang 94-98 weight reduced to 2550/2614/2678 lbs; 99-03 3.8L classified EP at 2700/2768/2835 lbs.
  • EP Improved Touring Tires #32064tyres & wheelsadded · tyres & wheelsEP, FP, HP Improved Touring cars may use any DOT-approved tyre as defined by 9.3.45.
  • FA Closing the Gap #31934enginefaster · engineFA Pro Formula Mazda now allows street port or bridge port; porting was previously not permitted.
  • FV Connecting Rod Update Request for 9.1.1.C Formula Vee (FV) 5.C.6 #32160engineadded · engineFV connecting rod options expanded to include BrianCrower part BC6417 and Newland Group part 4M113077.
  • FV E&O clarification of connecting rod center-to-center length #32183wordingwordingFV connecting rods minimum weight 425.0 grams, center-to-center length 130 +0.10/-0.25 mm; Crower, BrianCrower, Newland Group parts allowed if meeting specs.
  • EP Throttle Body and Idle Air #31800wordingwordingEP, FP, HP: stock/original idle control devices permitted unmodified or completely removed with openings blocked.
  • EP Porsche 968 Engine Questions #31831engineadded · engineEP Porsche 968 (92-95) now allowed to run dry sump.
  • EP Request weight reduction for 1979-1985 Mazda RX-7 #31833weightfaster · weightEP 1979-1985 Mazda RX-7 12A and 13B minimum weights cut 50–53 lbs across all spec lines.
  • FA Reorganize Tables 1 and 2 #31985cars addedaddedFA adds Honda K20Z3 2.0L at 1350 lbs and Mazda MZR 2.0L at 1300 lbs; removes 4A-GE 1.8L and MZR 2.0L from Table 2; raises 1615cc baseline to 1250 lbs.
  • AS Proposed Revisions to SCCA GCR 2021 Appendix M, Part 3 #30295wordingwordingSMG Long Tube Headers: Borla PN 17237 discontinued, approved alternatives American Racing MT3-05134300LSNC or Kooks PN 11312000.
  • AS specification line consolidation and correction #31846cars addedremoved · cars addedAS Mercury Capri 79-86 removed as separate spec line, merged into Ford Mustang 79-93 spec line.
  • AS correction of SMG specification line #31847wordingremovedAS Spec Mustang SMG Restricted Prep removes 3.73 gear ratio and 355/300 brake disc sizes.
  • AS Alternate cylinder heads for full prep engine builds - Evaluation #31851engineadded · engineAS Camaro, Firebird, Mustang full prep engines: alternate GM and Ford Performance cylinder heads permitted regionally with Allstar restrictor ALL26180.
  • EP Porsche 968 Engine Questions #31478engineengineEP Porsche 968 intake valve size changes to 39.0 mm, 1.54 mm seat width.
  • EP PCS E. 2. n. 4. Add Axle Shaft to Allow FWD the Same Freedom #31592otheraddedEP, FP, HP front-wheel-drive cars may alter body and subframes to install alternate axle shaft, matching RWD freedom.
  • EP BMW Z3 2.5L Spec Line #31724engineadded · engineEP BMW Z3 2.5L adds alternate throttle body option with Turner adapter and permits head casting 1738400.
  • FV Update direct replacement connecting rod information #31843wordingwordingFV Crower connecting rods SP93280B and BC6417 allowed as direct replacement, must meet OEM minimum weight.
  • EP 944S2 Restrictor #31396inductionslower · inductionEP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; compression ratio 12.0:1 max, valve lift 0.500" max, dry sump allowed.
  • EP Classing Clarification for 1986 Toyota Corolla FX16 #31527cars addedaddedToyota Corolla GTS RWD (84-87) and FX16 FWD (87-88) added to HP; old Corolla (84-87) removed.
  • FV Formula V Connecting Rod Replacement #31448engineadded · engineFV allows Crower SP93280B and Brian Crower Racing Rods connecting rods as direct replacements, matching OEM minimum weight.
  • AS Request for adjustable Front Upper Control Arms on 4th Gen F-Body #30457otheraddedAS Chevrolet/Pontiac Camaro & Firebird 93-02 gains BMR AA004 or UMI 2310 adjustable front upper control arms.
  • AS Request Pontiac GTO tire size change #30881weightslower · weightAS Pontiac GTO 04-06 Restricted Prep minimum weight rises: LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tires.
  • EP E&O; MR2 Track #31120suspension & brakessuspension & brakesToyota MR-2 1.6L 85-89 HP track width corrected to 15×47 / 15×47 inches; stock track baseline now 103% plus 2.5 inches.
Indianapolis Motor Speedway Runoffs 20212021-09-251:29.701James French · fastest of 18 · top 5 within 2.7s-0.256s (-0.28%)1:30.650James French · fastest of 17 · top 5 within 6.1s-0.715s (-0.78%)155.5James French1:50.427Drew Cattell · fastest of 31 · top 5 within 1.9s+5.207s (+4.95%)1:50.606Gregory Eaton · fastest of 28 · top 5 within 1.7s-0.901s (-0.81%)153.8James Jost+19.956squal +20.726s122.0%qual 123.1%1:57.479Andrew Whitston · fastest of 48 · top 5 within 0.8s+1.720s (+1.49%)1:57.234Alex Scaler · fastest of 47 · top 5 within 1.0s+1.311s (+1.13%)124.0Mark Edwards+26.584squal +27.778s129.3%qual 131.0%1:48.181Jesse Prather · fastest of 31 · top 5 within 3.2s-1.416s (-1.29%)1:49.928Jesse Prather · fastest of 27 · top 5 within 0.9s-0.468s (-0.42%)143.4Jon Brakke+19.278squal +18.480s121.3%qual 120.6%
50 rule changes (FA: 22, AS: 14, EP: 14)15 cars added · 8 weight · 5 engine · 2 induction · 16 wording · 4 other · FA Mazda MZR 2.0 engine name shortened to Mazda MZR; Honda Civic K20Z3 name clarified. · EP Honda S2000 now allows F22c engine in 1997cc and 2157cc displacements with revised weight brackets and specifications. · EP Nissan 240-SX S13/S14 weight drops to 2400 lbs base, 2460 turbo, 2520 supercharged; comp ratio raised to 12.0:1, valve lift to 0.500 inch. · Toyota 1800 moves from FA Table 1 to FA Table 2 Spec Line Cars. · FA Swift 016 Mazda MZR/Ford Duratec wheel width spec clarified: front 10, rear 14 min & 15 max inches. · EP Lotus/Caterham 7 America fuel injection permitted; IT preparation engine limitation removed. · Daimler SP 250 classified in EP with 2165 lbs minimum weight, 2548 cc eight-cylinder OHV engine, SU or Stromberg carburetors. · FA rule text reorganized: purpose-built and ex-pro cars moved to Table 1, spec line cars to Table 2, with clarified engine note applicability. · FA Mazda MZR/Ford Duratec 2296cc and 2500cc moved from Table 1 to Table 2. · FA Mazda MZR 2.0L and Honda Civic K20Z3 change from 5-speed sequential to 5-speed. · AS Cadillac CTS-V 6.0L LS6 removes 295-tire 50 lb penalty. · AS consolidates seven SN95 Mustang '94-'04 spec lines into three unified lines by model year and engine. · AS Camaro/Firebird LT1 and LS1 transmission changed to TUET1 6362; Mustang GT 4.6L/5spd to TUKT16901, loses 300 lbs. · AS Camaro & Firebird and Mustang GT gear ratio specifications restored with alternate sets permitted. · AS Camaro, Firebird, Mustang, and Capri all gain 50 lbs minimum weight across seven model year variants. · EP, FP, HP clarify percentage weight penalties sum before applying to base weight, round to nearest pound. · FA Mazda MZR 2.0 limited to Ralt RT40, RT41, Swift 008, 014 chassis; Honda Civic K20Z3 removes Swift 016 chassis. · 84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lb weight, 1998cc SOHC engine, two 32mm carburetors. · FP Fiat X1/9 and Bertone 1300 brake rotors now 257 x 12 mm, 10.1 inch diameter, 0.407 inch thickness. · EP Mazda MX-5 model year range corrected from 06-14 to 06-15. · FA Swift 016 2.3 liter engine name corrected to Mazda MZR/Ford Duratec. · FA Swift 016 2.5 liter engine name corrected to Mazda MZR/Ford Duratec. · FA removes four spec lines (E–H); spec line D changes from Ford Duratec/Mazda MZR 2500 to Honda B16 1615, loses 29mm restrictor, weight 1400 to 1175 lbs. · Mazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC four-cylinder, fuel injected with 55mm throttle body, comp ratio 12.0:1 max, valve lift 0.500" max. · FA Spec Lines C, I, K weights adjusted: C to 1175 lbs, I to 1175 lbs, K to 1175 lbs. · FA purpose-built and ex-Pro Atlantic cars remove sequential trans. 25 lb penalty redundant reference. · FA Ligier car name corrected to FR Americas Ligier JS F3. · FA Ford Duratec/Mazda MZR Spec Line D clarifies valve specification to 4 per cylinder, no performance change. · FA Honda Civic K20Z3 intake manifold and throttle body now may use AT Power Direct-To-Head 45mm individual throttle bodies PN 102-104-00020 as alternative. · AS Mustang 4.6L 5spd gains cold air intake freedom; 5.0L 6spd now requires 56mm flat plate restrictor. · AS CTS-V 5.7L LS6 and 6.0L LS2 may use Driveshaft Shop P/N GMCTSV2-C carbon fiber driveshaft. · AS Chevrolet Camaro SS V8 6.2L Restricted Prep model years extended from 10–13 to 10–15. · FA Ford Duratec/Mazda MZR intake restrictor reduced from 32mm to 30mm SIR; Swift 016 2.5 Mazda restrictor reduced from 35mm to 33mm SIR. · FA Toyota 4A-GE Spec Lines A and B: engine designation and valve configuration clarified, weights and displacement unchanged. · FA Ford BD Series engine displacement increases from 1600 cc to 1615 cc; minimum weight stays 1200 lbs. · FA Ford Duratec/Mazda MZR and Honda B16 engines both now limited to 1615cc displacement; both lose NA restrictor requirement. · Pro Formula Mazda engine specifications moved from Table 1 to Table 2 spec line notes; no performance changes. · AS Ford Mustang GT 5.0L 15-17 Restricted added to Spec Line with 3600 lbs minimum weight, 55mm restrictor, 18×10 wheels, 295 tires. · AS underhood bracing on stock hoods, trunks, and rear decks may be modified or removed. · AS Cadillac CTS-V 04-07 with 295 tire drops to 3450 lbs; Camaro SS V8 10-13 and Challenger 08-20 specs removed. · AS Camaro & Firebird (93-02) and Mustang GT (05-14) specifications restored with weight minimums 3250–3500 and 3350–3600 lbs respectively. · EP Austin-Healey 3000 gains option to use TR-6 front calipers and discs as alternate. · Formula Lites Crawford FL15 added to FA classification effective 2021-01-01. · AS Dodge Challenger gains 6.1L and 6.4L V8 options; 5.7L weight rises to 3500 lbs on 295 tyres, 3600 on 315 tyres; compression to 10.9:1 max. · AS Camaro & Firebird (93-02) and Ford Mustang Coupe GT (05-14) spec lines consolidated; Camaro/Firebird now allows both LT1 and LS1 engines; Mustang now allows both 4.6L 3-valve and 5.0L 4-valve engines with restrictor. · FP Mk2 Golf and Jetta 1.8 lose 50 lbs to 1900; HP Jetta GLI engine code removed. · EP, FP, HP Level 1 and Level 2 induction systems: carburettor jets, needles, metering rods allowed; throttle body porting permitted; wording clarified. · EP Nissan Datsun SRL 311U Roadster minimum weight reduced 75 lbs to 1925. · EP Triumph TR8 78-81 minimum weight drops to 2500 lbs.showhide
  • FA E&O Table 2 engine names #31085wordingwordingFA Mazda MZR 2.0 engine name shortened to Mazda MZR; Honda Civic K20Z3 name clarified.
  • EP Request to Allow F22c Engine for 2000-2003 Honda S2000 #30548cars addedaddedEP Honda S2000 now allows F22c engine in 1997cc and 2157cc displacements with revised weight brackets and specifications.
  • EP Request a review of the S14 240SX in EP. #30873weight -200 lbsfaster · weightEP Nissan 240-SX S13/S14 weight drops to 2400 lbs base, 2460 turbo, 2520 supercharged; comp ratio raised to 12.0:1, valve lift to 0.500 inch.
  • FA Move Toyota 1800 to Table 2 #30822cars addedcars addedToyota 1800 moves from FA Table 1 to FA Table 2 Spec Line Cars.
  • FA E&O Swift 016 wheel width reference #30939wordingwordingFA Swift 016 Mazda MZR/Ford Duratec wheel width spec clarified: front 10, rear 14 min & 15 max inches.
  • EP Lotus/Caterham 7 America Request #30392wordingwordingEP Lotus/Caterham 7 America fuel injection permitted; IT preparation engine limitation removed.
  • EP Reclassify Daimler SP 250 #30721cars addedaddedDaimler SP 250 classified in EP with 2165 lbs minimum weight, 2548 cc eight-cylinder OHV engine, SU or Stromberg carburetors.
  • FA Update FA rules package #30717wordingwordingFA rule text reorganized: purpose-built and ex-pro cars moved to Table 1, spec line cars to Table 2, with clarified engine note applicability.
  • FA Move Mazda MZR/Ford Duratec 2296cc and 2500cc to Table 2 #30718cars addedaddedFA Mazda MZR/Ford Duratec 2296cc and 2500cc moved from Table 1 to Table 2.
  • FA Clean up Table 2 Mazda MZR 2.0L and Honda Civic K20Z3 spec lines #30719wordingwordingFA Mazda MZR 2.0L and Honda Civic K20Z3 change from 5-speed sequential to 5-speed.
  • AS Request CTS-V Spec Line Error Correction #30242weightfaster · weightAS Cadillac CTS-V 6.0L LS6 removes 295-tire 50 lb penalty.
  • AS Request to consolidate SN95 Mustang '94-'04 Mustang spec lines #30428wordingwordingAS consolidates seven SN95 Mustang '94-'04 spec lines into three unified lines by model year and engine.
  • AS American Sedan Transmission Rule Change Request #30595enginefaster · engineAS Camaro/Firebird LT1 and LS1 transmission changed to TUET1 6362; Mustang GT 4.6L/5spd to TUKT16901, loses 300 lbs.
  • AS Correction to specifications inadvertently deleted #30691wordingwordingAS Camaro & Firebird and Mustang GT gear ratio specifications restored with alternate sets permitted.
  • AS weight adjustments #30700weight +50 lbsslower · weightAS Camaro, Firebird, Mustang, and Capri all gain 50 lbs minimum weight across seven model year variants.
  • EP Clarify Application of Percentage Based Weight Penalties #30669wordingwordingEP, FP, HP clarify percentage weight penalties sum before applying to base weight, round to nearest pound.
  • FA E&O Mazda MZR 2.0 and Honda Civic K20Z3 chassis eligibility #30632cars addedremoved · cars addedFA Mazda MZR 2.0 limited to Ralt RT40, RT41, Swift 008, 014 chassis; Honda Civic K20Z3 removes Swift 016 chassis.
  • EP Change Classification of 84-87 Mazda 626 from FP to HP #30350cars addedadded84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lb weight, 1998cc SOHC engine, two 32mm carburetors.
  • EP Fiat X1/9 brake rotors #30423otherotherFP Fiat X1/9 and Bertone 1300 brake rotors now 257 x 12 mm, 10.1 inch diameter, 0.407 inch thickness.
  • EP NC MX-5 year range correction E&O #30503cars addedaddedEP Mazda MX-5 model year range corrected from 06-14 to 06-15.
  • FA Correct engine name in Swift 016 2.3 liter spec line #30447wordingwordingFA Swift 016 2.3 liter engine name corrected to Mazda MZR/Ford Duratec.
  • FA Correct engine name in Swift 016 2.5 liter spec line #30448wordingwordingFA Swift 016 2.5 liter engine name corrected to Mazda MZR/Ford Duratec.
  • FA Revise Table 1 Spec Lines and clarify application of Engine Notes #30456cars addedfaster · cars addedFA removes four spec lines (E–H); spec line D changes from Ford Duratec/Mazda MZR 2500 to Honda B16 1615, loses 29mm restrictor, weight 1400 to 1175 lbs.
  • EP Please Classify Mazda3 in FP #30165cars addedaddedMazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC four-cylinder, fuel injected with 55mm throttle body, comp ratio 12.0:1 max, valve lift 0.500" max.
  • FA Update Table 1 Weights for Spec Lines C, I, and K #30355weight -25 lbsfaster · weightFA Spec Lines C, I, K weights adjusted: C to 1175 lbs, I to 1175 lbs, K to 1175 lbs.
  • FA Remove redundant reference in Table 2 spec line #30366wordingwordingFA purpose-built and ex-Pro Atlantic cars remove sequential trans. 25 lb penalty redundant reference.
  • FA Correct the name of the FR Americas car #30369wordingwordingFA Ligier car name corrected to FR Americas Ligier JS F3.
  • FA Clean up Spec Line D in Table 1 #30372wordingwordingFA Ford Duratec/Mazda MZR Spec Line D clarifies valve specification to 4 per cylinder, no performance change.
  • FA Table 2 Honda K20Z3 request #30386engineadded · engineFA Honda Civic K20Z3 intake manifold and throttle body now may use AT Power Direct-To-Head 45mm individual throttle bodies PN 102-104-00020 as alternative.
  • AS AS Mustang LP 4.6 3V Classification Transmission Request #29886enginefaster · engineAS Mustang 4.6L 5spd gains cold air intake freedom; 5.0L 6spd now requires 56mm flat plate restrictor.
  • AS Request CF driveshaft on CTS-V for durability improvement #30117otheraddedAS CTS-V 5.7L LS6 and 6.0L LS2 may use Driveshaft Shop P/N GMCTSV2-C carbon fiber driveshaft.
  • AS Adjustment to model years of 5th generation RP Camaro #30348cars addedaddedAS Chevrolet Camaro SS V8 6.2L Restricted Prep model years extended from 10–13 to 10–15.
  • FA E&O FA Intake Restrictors #30273inductionslower · inductionFA Ford Duratec/Mazda MZR intake restrictor reduced from 32mm to 30mm SIR; Swift 016 2.5 Mazda restrictor reduced from 35mm to 33mm SIR.
  • FA Clean up Spec Lines A and B in Table 1 #30274wordingwordingFA Toyota 4A-GE Spec Lines A and B: engine designation and valve configuration clarified, weights and displacement unchanged.
  • FA Clean up Spec Line C in Table 1 #30275enginefaster · engineFA Ford BD Series engine displacement increases from 1600 cc to 1615 cc; minimum weight stays 1200 lbs.
  • FA Clean up Spec Lines J and L in Table 1 #30276engineengineFA Ford Duratec/Mazda MZR and Honda B16 engines both now limited to 1615cc displacement; both lose NA restrictor requirement.
  • FA Move engine specifications to Pro Formula Mazda spec line notes #30278wordingwordingPro Formula Mazda engine specifications moved from Table 1 to Table 2 spec line notes; no performance changes.
  • FA Update F3 Americas spec line #30280other
  • AS Request for 2015 -2017 Ford Mustang Spec Line #29514cars addedaddedAS Ford Mustang GT 5.0L 15-17 Restricted added to Spec Line with 3600 lbs minimum weight, 55mm restrictor, 18×10 wheels, 295 tires.
  • AS Request Trunk lid / Rear Hatch clarification #29591wordingwordingAS underhood bracing on stock hoods, trunks, and rear decks may be modified or removed.
  • AS Common Weight for CTS-V Tire #29759weightfaster · weightAS Cadillac CTS-V 04-07 with 295 tire drops to 3450 lbs; Camaro SS V8 10-13 and Challenger 08-20 specs removed.
  • AS Correction to specifications inadvertently deleted #30041cars addedaddedAS Camaro & Firebird (93-02) and Mustang GT (05-14) specifications restored with weight minimums 3250–3500 and 3350–3600 lbs respectively.
  • EP Alternate Front Brake Rotors and Calipers for EP AH 3000 #29893otherotherEP Austin-Healey 3000 gains option to use TR-6 front calipers and discs as alternate.
  • FA Request to classify Formula Lites Crawford FL15 #29702cars addedaddedFormula Lites Crawford FL15 added to FA classification effective 2021-01-01.
  • AS Request Additional Engine Options for Dodge Challenger Spec Line #29543cars addedaddedAS Dodge Challenger gains 6.1L and 6.4L V8 options; 5.7L weight rises to 3500 lbs on 295 tyres, 3600 on 315 tyres; compression to 10.9:1 max.
  • AS Rule simplification spec line communization #29824cars addedcars addedAS Camaro & Firebird (93-02) and Ford Mustang Coupe GT (05-14) spec lines consolidated; Camaro/Firebird now allows both LT1 and LS1 engines; Mustang now allows both 4.6L 3-valve and 5.0L 4-valve engines with restrictor.
  • EP Mk2 VW Consistency and Cleanup of FP and HP Spec Lines #29195weight -50 lbsfaster · weightFP Mk2 Golf and Jetta 1.8 lose 50 lbs to 1900; HP Jetta GLI engine code removed.
  • EP Correct Wording for Level 1 and Level 2 Induction Systems #29406inductionfaster · inductionEP, FP, HP Level 1 and Level 2 induction systems: carburettor jets, needles, metering rods allowed; throttle body porting permitted; wording clarified.
  • EP Weight Reduction for Datsun Roadster #29409weight -75 lbsfaster · weightEP Nissan Datsun SRL 311U Roadster minimum weight reduced 75 lbs to 1925.
  • EP EP TR8 Adjustment #29512weight -100 lbsfaster · weightEP Triumph TR8 78-81 minimum weight drops to 2500 lbs.
Road America Runoffs 20202020-10-022:04.274Spencer Brockman · fastest of 11 · top 5 within 2.7s2:04.746Spencer Brockman · fastest of 10 · top 5 within 2.4s150.6Hans Peter2:27.045Gregory Eaton · fastest of 18 · top 5 within 0.6s2:27.668Gregory Eaton · fastest of 15 · top 5 within 1.5s149.2Gregory Eaton+22.922squal +22.771s118.4%qual 118.3%2:43.994Hunter Phelps-Barron · fastest of 28 · top 5 within 0.6s2:45.816Alex Scaler · fastest of 24 · top 5 within 1.5s117.1Hunter Phelps-Barron+41.070squal +39.720s132.9%qual 132.0%2:27.322Jesse Prather · fastest of 20 · top 5 within 2.5s2:29.047Jesse Prather · fastest of 20 · top 5 within 2.8s141.7Jesse Prather+24.301squal +23.048s119.5%qual 118.5%
51 rule changes (FA: 15, AS: 16, FV: 6, EP: 14)9 engine · 6 cars added · 6 tyres & wheels · 3 induction · 3 weight · 1 aero · 1 suspension & brakes · 19 wording · 3 other · HP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches. · AS Dodge Challenger 5.7L V8 now requires iron block instead of aluminum, compression to 10.5:1 max, intake valve 12.7 mm, exhaust 12.3 mm, intake timing 188 degrees, exhaust timing 205 degrees. · AS Dodge Challenger 08-14 rear spoiler: 1GL20RXF replaced with 1GL20TZZAB; 82211606 still permitted. · EP BMW Z3 2.5L cylinder head casting 1738400 permitted with iron block castings 1748933 or 1738566. · AS class pursuing specified list of eligible tires; list details unclear from text provided. · AS class tire eligibility list under development; no specifications changed yet. · AS Coyote Mustang restrictor plate under review for 2021; no change effective yet. · AS Restricted Prep 4.6 3V now permits conversion to 2 valve configuration. · AS Ford Mustang Coupe GT 4.6L 3V Restricted Prep now permits Ford Performance camshaft kit P/N M-6550-3V. · 2010-2014 Camaro remains classified in AS; no specification changes. · AS class cylinder head supplier discontinuation; replacement option pending for 2021 season. · AS Mustang, Capri, Camaro, and Firebird maximum brake rotor diameter increased from 12.2 to 13.1 inches. · unclear · Porsche 911 S 67-68 classified in EP at 1800–1890 lbs, 1991cc opposed 6-cylinder SOHC with 36mm carburetors. · FA stock engine weight adjustment request denied; modified engines now permitted in FA. · FV now permits 4 bolt wheels in addition to existing specifications. · FV now allows 4-bolt pattern wheels in addition to existing specifications. · EP BMW 2.8L, 328i E36/E46, and 325i E36 now require iron blocks only; 325i E46 aluminum block removed. · FA engine modifications clarified: bore/stroke/flywheel unrestricted within displacement limits, distributor/ignition installation restricted, compression ratio machining allowed, table references updated. · FA transmissions limited to five forward speeds and operational reverse unless Table 2 notes otherwise. · FA Swift 016 Mazda Duratec: clarify Gurney flap wording, dimensions and allowed locations unchanged. · FP Pre: 1990–1994 Mazda Protégé classified at 2150–2258 lbs, 1839cc DOHC, fuel injection, 11.0:1 compression, .450" valve lift limit. · HP Mini Cooper 02-06 and 07-13 convertible model years corrected to 05-08 and 09-15 respectively. · FA removes Volkswagen 1835cc SOHC engine specification line from Table 1. · FA engine rules clarify that blocks and heads must be OEM unless the tables note otherwise; wording only. · EP Caterham 7 America engine limited to IT prep with specific sections, comp ratio 10.0:1, valve lift .380 inch. · FA Formula 1000 motorcycle-based engines gain maximum compression ratio of 14.5:1, up from 13.5:1. · FA removes Ex-FSV wheel width rules, all cars now front ten inches, rear fourteen to fifteen inches. · FA Formula 3 permitted engine years extended from 1997–2008 to 1997–2017. · EP BMW 325is M-Technic 1994 minimum weight cut to 2550 lbs, modifier weights to 2614 and 2678. · HP Datsun 510 allows 40 DCOE carburetor option alongside existing 40 DCNF and 36mm DCNVH; auto side drafts moved to penalty structure. · EP fuel-injected BMW throttle body maximum inside diameter set to 64 mm. · FA Table 1 engine notes now apply only to Table 1, not Table E; FA Table 2 Pro Formula Mazda engine references Table 1 specs. · FV rain tyre changes to Hoosier #44266 22.5 x 5.0 x 15 WET or W3. · AS rear trailing arms may be replaced with tubular arms maintaining stock length and axle location purpose only. · AS Ford and GM full prep cars get increased weight reduction from 150 to 200 lbs. · 05-10 Ford Mustang Coupe GT 4.6L OHC classified AS with 3200 lbs minimum weight, HR cam permitted. · 10-15 Camaro Full Prep classified AS with 3400 lbs base weight, 3700 lbs over 313 CID, specific head castings and Edelbrock heads permitted. · HP Datsun 1200 carburetor option changes from 26mm to 30mm choke(s) in 40 DCN, DCNF, IDF. · Mazda Miata models EP and FP throttle body specified 55mm, brake rotor thickness figures removed. · Formula 1000 motorcycle-based engine up to 1000cc added to FA with unrestricted throttle bodies and ECUs. · unclear · FA Swift 016 2.3L Mazda Duratec restrictor reduced from 33mm to 31mm SIR. · FV allows non-spec Hoosier tyres at Regional races only; Majors, Super Tour, and Runoffs require spec tyres from 1/1/2020. · Formula Vee now allows 22.5 x 5.5 x 15 rear tires on front axle; rain tire mandated as Hoosier #44266 22.5 x 5.0 x 15 from 1/1/2020. · EP, FP, HP cylinder head rules reorganized for clarity; no performance change. · FA wheel diameter and width specifications moved from Bodywork subsection to General section. · FA Mazda MZR 2.0 engine use restricted to Ralt RT40, Ralt RT41, and Swift 014 chassis only. · FV wheels may now be 15-inch 4.5J steel VW with same 5-bolt pattern as standard 4J, within track limits.showhide
  • EP 84-87 Toyota Corolla HP Wheel Diameter Allowance Proposal E&O #29458otherfasterHP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches.
  • AS Dodge Challenger AS Spec Line Clarification #28698engineslower · engineAS Dodge Challenger 5.7L V8 now requires iron block instead of aluminum, compression to 10.5:1 max, intake valve 12.7 mm, exhaust 12.3 mm, intake timing 188 degrees, exhaust timing 205 degrees.
  • AS Dodge Challenger AS Spec Line Clarification #2 #28699aeroaeroAS Dodge Challenger 08-14 rear spoiler: 1GL20RXF replaced with 1GL20TZZAB; 82211606 still permitted.
  • EP EP BMW Z3 Rule Clarification #28998wordingwordingEP BMW Z3 2.5L cylinder head casting 1738400 permitted with iron block castings 1748933 or 1738566.
  • AS Support for R-Type Specification Tires #27450wordingunclearAS class pursuing specified list of eligible tires; list details unclear from text provided.
  • AS Spec Tire Request #27519wordingunclearAS class tire eligibility list under development; no specifications changed yet.
  • AS Restrictor Plate Change for RP 2011+ Mustang with Coyote Engine #27675wordingunclearAS Coyote Mustang restrictor plate under review for 2021; no change effective yet.
  • AS 2005-2009 Restricted Prep 4.6 3V #27908engineadded · engineAS Restricted Prep 4.6 3V now permits conversion to 2 valve configuration.
  • AS Request for 2005-2009 Restricted Prep 4.6 3V Parts #27909engineadded · engineAS Ford Mustang Coupe GT 4.6L 3V Restricted Prep now permits Ford Performance camshaft kit P/N M-6550-3V.
  • AS Request for Full Preparation Classification for 2010-2014 Camaro #28030wordingunclear2010-2014 Camaro remains classified in AS; no specification changes.
  • AS Cylinder Heads #28696wordingunclearAS class cylinder head supplier discontinuation; replacement option pending for 2021 season.
  • AS Request for Max Rotor Diameter Change #28748otherfasterAS Mustang, Capri, Camaro, and Firebird maximum brake rotor diameter increased from 12.2 to 13.1 inches.
  • AS Request increase rotor diameter #28797wordingunclearunclear
  • EP Request to Classify Porsche 911 2.0L #28456cars addedaddedPorsche 911 S 67-68 classified in EP at 1800–1890 lbs, 1991cc opposed 6-cylinder SOHC with 36mm carburetors.
  • FA Request to Adjust FB Weight for Stock Engines #29005wordingunclearFA stock engine weight adjustment request denied; modified engines now permitted in FA.
  • FV Support for Recommended Item - 4 bolt wheels in FV #29084cars addedaddedFV now permits 4 bolt wheels in addition to existing specifications.
  • FV Support for 4-bolt pattern wheels #28955 #29118tyres & wheelsadded · tyres & wheelsFV now allows 4-bolt pattern wheels in addition to existing specifications.
  • EP BMW Cylinder Head Casting and Part Numbers #28708engineslower · engineEP BMW 2.8L, 328i E36/E46, and 325i E36 now require iron blocks only; 325i E46 aluminum block removed.
  • FA E&O permitted engine modifications #28831wordingwordingFA engine modifications clarified: bore/stroke/flywheel unrestricted within displacement limits, distributor/ignition installation restricted, compression ratio machining allowed, table references updated.
  • FA E&O Transmissions #28832wordingwordingFA transmissions limited to five forward speeds and operational reverse unless Table 2 notes otherwise.
  • FA Swift 016 Gurney flap wicker clarification #28884wordingwordingFA Swift 016 Mazda Duratec: clarify Gurney flap wording, dimensions and allowed locations unchanged.
  • AS weight adjustments for 2020 season #28785weight -50 lbs
  • EP Request to Classify 1990-1994 Mazda Protege #28381cars addedaddedFP Pre: 1990–1994 Mazda Protégé classified at 2150–2258 lbs, 1839cc DOHC, fuel injection, 11.0:1 compression, .450" valve lift limit.
  • EP Error in Mini Cooper Spec Line #28713wordingwordingHP Mini Cooper 02-06 and 07-13 convertible model years corrected to 05-08 and 09-15 respectively.
  • FA Remove redundant spec line in Table 1 #28720engineremoved · engineFA removes Volkswagen 1835cc SOHC engine specification line from Table 1.
  • FA E&O general engine rules #28772wordingwordingFA engine rules clarify that blocks and heads must be OEM unless the tables note otherwise; wording only.
  • EP Caterham 7 Spec Line #28498wordingwordingEP Caterham 7 America engine limited to IT prep with specific sections, comp ratio 10.0:1, valve lift .380 inch.
  • FA Request higher compression ratio and prior weights for F1000 cars #28162enginefaster · engineFA Formula 1000 motorcycle-based engines gain maximum compression ratio of 14.5:1, up from 13.5:1.
  • FA Remove redundant wheel dimension provisions #28554tyres & wheelstyres & wheelsFA removes Ex-FSV wheel width rules, all cars now front ten inches, rear fourteen to fifteen inches.
  • FA E&O Formula 3 spec line #28596engineadded · engineFA Formula 3 permitted engine years extended from 1997–2008 to 1997–2017.
  • EP Request to Review Horsepower Parity #27662induction
  • EP E36 (92-95) Brakes Errors and Omissions #28058weightfaster · weightEP BMW 325is M-Technic 1994 minimum weight cut to 2550 lbs, modifier weights to 2614 and 2678.
  • EP Request to allow 40 DCOE carb for the Datsun 510 #28195engineadded · engineHP Datsun 510 allows 40 DCOE carburetor option alongside existing 40 DCNF and 36mm DCNVH; auto side drafts moved to penalty structure.
  • EP Add Throttle Body Size these EP BMW Spec Lines #28422engineslower · engineEP fuel-injected BMW throttle body maximum inside diameter set to 64 mm.
  • FA FA weight correction/clarification #28430wordingwordingFA Table 1 engine notes now apply only to Table 1, not Table E; FA Table 2 Pro Formula Mazda engine references Table 1 specs.
  • FV Update rain tire designation #28444tyres & wheelstyres & wheelsFV rain tyre changes to Hoosier #44266 22.5 x 5.0 x 15 WET or W3.
  • AS Rear Trailing Arms #28007suspension & brakesadded · suspension & brakesAS rear trailing arms may be replaced with tubular arms maintaining stock length and axle location purpose only.
  • AS Weight reduction for cars running iron heads #28010weightfaster · weightAS Ford and GM full prep cars get increased weight reduction from 150 to 200 lbs.
  • AS 05-10 Mustang with HR cam classification #28226cars addedadded05-10 Ford Mustang Coupe GT 4.6L OHC classified AS with 3200 lbs minimum weight, HR cam permitted.
  • AS 10-15 Camaro Full Prep classification #28227cars addedadded10-15 Camaro Full Prep classified AS with 3400 lbs base weight, 3700 lbs over 313 CID, specific head castings and Edelbrock heads permitted.
  • EP Request for Help for Datsun 1200 #27934inductionfaster · inductionHP Datsun 1200 carburetor option changes from 26mm to 30mm choke(s) in 40 DCN, DCNF, IDF.
  • EP Request to List Mazda Miata Throttle Body Size #27907wordingwordingMazda Miata models EP and FP throttle body specified 55mm, brake rotor thickness figures removed.
  • FA Request to merge FB into FA #25611cars addedaddedFormula 1000 motorcycle-based engine up to 1000cc added to FA with unrestricted throttle bodies and ECUs.
  • FA Suggestions for FB/F1000 into FA #27319otherunclearunclear
  • FA Change Swift 016 - 2.3 liter Mazda Duratec restrictor size #27880inductionslower · inductionFA Swift 016 2.3L Mazda Duratec restrictor reduced from 33mm to 31mm SIR.
  • FV FV Allow non-spec tire in Regional competition #26284tyres & wheelsadded · tyres & wheelsFV allows non-spec Hoosier tyres at Regional races only; Majors, Super Tour, and Runoffs require spec tyres from 1/1/2020.
  • FV Request to Allow Rear Tires on the Front of Formula Vee #26537tyres & wheelsadded · tyres & wheelsFormula Vee now allows 22.5 x 5.5 x 15 rear tires on front axle; rain tire mandated as Hoosier #44266 22.5 x 5.0 x 15 from 1/1/2020.
  • EP Re-organize Prep2 Cylinder Head Rules for Clarity & Consistency #27661wordingwordingEP, FP, HP cylinder head rules reorganized for clarity; no performance change.
  • FA Move wheel dimensions from Bodywork subsection to #27493wordingwordingFA wheel diameter and width specifications moved from Bodywork subsection to General section.
  • FA Table 2 Mazda MZR 2.0 E&O #27640wordingwordingFA Mazda MZR 2.0 engine use restricted to Ralt RT40, Ralt RT41, and Swift 014 chassis only.
  • FV Clarification on Wheel Bolt Pattern #27603tyres & wheelsadded · tyres & wheelsFV wheels may now be 15-inch 4.5J steel VW with same 5-bolt pattern as standard 4J, within track limits.
Virginia International Raceway Runoffs 20192019-10-051:41.545Dario Cangialosi · fastest of 8 · top 5 within 2.8s1:43.107Dario Cangialosi · fastest of 8 · top 5 within 1.8s155.9Kent Vaccaro2:02.938Gregory Eaton · fastest of 17 · top 5 within 0.8s2:03.900James Jost · fastest of 16 · top 5 within 2.1s153.9James Jost+20.793squal +21.393s120.2%qual 121.1%2:15.712Andrew Whitston · fastest of 26 · top 5 within 1.5s2:18.289Zachary Whitston · fastest of 19 · top 5 within 0.4s114.8Roger Siebenaler+35.182squal +34.167s134.1%qual 133.6%2:00.987Jesse Prather · fastest of 29 · top 5 within 2.2s2:01.631Jesse Prather · fastest of 24 · top 5 within 1.4s147.5Kip Van Steenburg+18.524squal +19.442s118.0%qual 119.1%
27 rule changes (FA: 7, AS: 4, FV: 6, EP: 10)5 weight · 4 cars added · 3 engine · 2 aero · 1 induction · 1 removed · 1 suspension & brakes · 1 tyres & wheels · 8 wording · 1 other · AS Spec Mustang (SMG) added as Restricted Prep class. · FA Honda Civic K20Z3 engine for Swift 014 and 016 chassis consolidated to single spec line with 1350 lbs minimum weight. · FV exhaust exit opening repositioned: minimum one inch, maximum four inches behind rear body. · FP and HP Austin-Healey Sprite Mk I / MG Midget may replace rear bodywork aft of cockpit with alternate material stock-appearing components. · EP Mazda MX-5 Global Cup classification updated to include 2019 model year. · Production classes: suspension rule clarified to specify spindles, hubs, bushings, bearings, and ball joints unrestricted. · Production carburetor and fuel injection rules clarified: permitted optional carburetors listed, Weber and auto-type substitutions specified, fuel injection throttle body and butterfly dimensions detailed, intake manifold port extension pr… · EP, FP, HP carburetors: jets, needles, metering rods, needle valves unrestricted; choke parts removable; stock or optional Weber 40 DCN permitted; Weber types, auto types listed. · FA Swift 014 Mazda MZR 2.0 piston minimum weight drops from 320g to 280g; maximum dome height limit removed. · FV allows fifteen-inch steel wheels at 4J or 4.5J width, standard VW sedan or within track dimensions. · AS class ride height minimum clarified: five inches measured at rocker panel, excluding seams and stock effects. · EP Mazda MX-5/Miata model years expand from 1999-2002 to 1999-2005. · AS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450. · FA Line N minimum weight raised to 1375 lbs. · FV exhaust outlet opening max distance from body rear increased from 3 to 4 inches. · EP Mazda RX-8 firewall may be modified for 13B engine fitment and must be sealed. · FA cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs. · FV front track maximum 52.500 inches; rear track 49.125–50.750 inches; spacers now allowed. · EP, FP, HP: clarified that tapered holes in ball joints can be reamed for bolt conversion, and wheel bearings and hubs unrestricted on all axles. · EP open cars may now use aftermarket hardtops if OEM-appearance and non-carbon-fiber; specific model allowances removed as redundant. · FV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement of 1.65 lbs removed. · EP Mazda RX-7 12A and 13B (79-85) lose up to 75 lbs; 13B (86-91) loses up to 79 lbs across three weight classes. · FA Formula 3 car transmission rules clarified: up to 6 forward gears, limited-slip differential, sequential removed, 25 lb penalty deleted. · AS adds Spec Mustang SMG classification with 107.1 wheelbase, 3.73 gears, 355mm front and 300mm rear brakes. · FA Swift 014-Mazda MZR 2.0 engine no longer sealed by Elite Engines; block, crank, rods, head, cams, manifold now specified with part numbers and dimensions. · FA Swift 016 Mazda 2.3 and 2.5 liter minimum weight increases 30 lbs to 1450. · FV intake manifold horizontal tube measurement location clarified; removed specific distance ranges from rule text.showhide
  • AS Request to add SMG to 9.1.6.B.1 AS Intent #27140cars addedaddedAS Spec Mustang (SMG) added as Restricted Prep class.
  • FA Follow up to Letter #27344 on Honda Powered FA Rules #27363removedremovedFA Honda Civic K20Z3 engine for Swift 014 and 016 chassis consolidated to single spec line with 1350 lbs minimum weight.
  • FV Allowed Modifications E&O #27398wordingwordingFV exhaust exit opening repositioned: minimum one inch, maximum four inches behind rear body.
  • EP Request bodywork for Austin Healey Bugeye Sprite MK1 #27106aeroadded · aeroFP and HP Austin-Healey Sprite Mk I / MG Midget may replace rear bodywork aft of cockpit with alternate material stock-appearing components.
  • EP Request to classify the GMX5 2019 #27263cars addedaddedEP Mazda MX-5 Global Cup classification updated to include 2019 model year.
  • EP level one susp. component rule #27270wordingwordingProduction classes: suspension rule clarified to specify spindles, hubs, bushings, bearings, and ball joints unrestricted.
  • EP Clarification of Carb Rules - Prep 1 #27300wordingwordingProduction carburetor and fuel injection rules clarified: permitted optional carburetors listed, Weber and auto-type substitutions specified, fuel injection throttle body and butterfly dimensions detailed, intake manifold port extension pr…
  • EP Clarification of Carb Rules - Prep 2 #27301inductioninductionEP, FP, HP carburetors: jets, needles, metering rods, needle valves unrestricted; choke parts removable; stock or optional Weber 40 DCN permitted; Weber types, auto types listed.
  • FA Swift 014 Mazda MZR 2.0 E&O #27305enginefaster · engineFA Swift 014 Mazda MZR 2.0 piston minimum weight drops from 320g to 280g; maximum dome height limit removed.
  • FV E&O Wheels #27230tyres & wheelsadded · tyres & wheelsFV allows fifteen-inch steel wheels at 4J or 4.5J width, standard VW sedan or within track dimensions.
  • AS Request Ride Height Clarification #26598wordingwordingAS class ride height minimum clarified: five inches measured at rocker panel, excluding seams and stock effects.
  • EP Request Miata Eligibility - 2003 #27121cars addedaddedEP Mazda MX-5/Miata model years expand from 1999-2002 to 1999-2005.
  • AS Request to Revert to 2017 Weights #25885weightfaster · weightAS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450.
  • FA Adjust Line N restrictor size and minimum weight #26691weight +30 lbsslower · weightFA Line N minimum weight raised to 1375 lbs.
  • FV Exhaust termination rule E&O #26702wordingwordingFV exhaust outlet opening max distance from body rear increased from 3 to 4 inches.
  • EP Allow Firewall Modification for Fitment of 13B into RX8 #26726engineadded · engineEP Mazda RX-8 firewall may be modified for 13B engine fitment and must be sealed.
  • FA Add data plate requirement #26707otheraddedFA cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs.
  • FV E&O Dimensions #26674suspension & brakessuspension & brakesFV front track maximum 52.500 inches; rear track 49.125–50.750 inches; spacers now allowed.
  • EP Rollcenter Correction Clarification #25873wordingaddedEP, FP, HP: clarified that tapered holes in ball joints can be reamed for bolt conversion, and wheel bearings and hubs unrestricted on all axles.
  • EP Hardtops #26476aeroadded · aeroEP open cars may now use aftermarket hardtops if OEM-appearance and non-carbon-fiber; specific model allowances removed as redundant.
  • FV Request to clarify Disc Brake rules bearing retainer & weights #26262weightslower · weightFV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement of 1.65 lbs removed.
  • EP Request for Competition Adjustment for 2nd Generation RX7 #25935weight -50 lbsfaster · weightEP Mazda RX-7 12A and 13B (79-85) lose up to 75 lbs; 13B (86-91) loses up to 79 lbs across three weight classes.
  • FA Request to add FA engine spec lines #26183wordingwordingFA Formula 3 car transmission rules clarified: up to 6 forward gears, limited-slip differential, sequential removed, 25 lb penalty deleted.
  • AS SMG Mustang eligibility in American sedan #26224cars addedaddedAS adds Spec Mustang SMG classification with 107.1 wheelbase, 3.73 gears, 355mm front and 300mm rear brakes.
  • FA FA MZR 2.0 Engine Specification #25814engineengineFA Swift 014-Mazda MZR 2.0 engine no longer sealed by Elite Engines; block, crank, rods, head, cams, manifold now specified with part numbers and dimensions.
  • FA FA 016 weight increase #26063weightslower · weightFA Swift 016 Mazda 2.3 and 2.5 liter minimum weight increases 30 lbs to 1450.
  • FV FV Intake Manifold Clarification #26008wordingwordingFV intake manifold horizontal tube measurement location clarified; removed specific distance ranges from rule text.
Sonoma Raceway Runoffs 20182018-10-101:28.176Mirl Swan · fastest of 7 · top 5 within 4.0s1:29.924Mirl Swan · fastest of 7 · top 5 within 2.6s144.8Antony Opheim1:47.782Andrew McDermid · fastest of 12 · top 5 within 1.9s1:50.345John Heinricy · fastest of 10 · top 5 within 2.3s105.0Kevin Fandozzi+20.421squal +19.606s122.7%qual 122.2%1:52.637Skip Streets · fastest of 29 · top 5 within 1.6s1:53.639Alex Scaler · fastest of 28 · top 5 within 0.4s106.3Skip Streets+23.715squal +24.461s126.4%qual 127.7%1:45.828Glen McCready · fastest of 18 · top 5 within 4.3s1:46.518Glen McCready · fastest of 16 · top 5 within 2.8s106.5Aaron Downey+16.594squal +17.652s118.5%qual 120.0%
No rule changes on record between these events
Indianapolis Motor Speedway Runoffs 20172017-09-251:29.957Sedat Yelkin · fastest of 12 · top 5 within 2.3s1:31.365Keith Grant · fastest of 12 · top 5 within 1.0s1:45.220James Jost · fastest of 29 · top 5 within 6.7s1:51.507Bryan Long · fastest of 28 · top 5 within 0.9s+20.142squal +15.263s122.0%qual 117.0%1:55.759Michael Varacins · fastest of 39 · top 5 within 1.0s1:55.923Michael Varacins · fastest of 32 · top 5 within 1.3s+24.558squal +25.802s126.9%qual 128.7%1:49.597Matt Reynolds · fastest of 44 · top 5 within 1.2s1:50.396Matt Reynolds · fastest of 45 · top 5 within 0.5s+19.031squal +19.640s120.8%qual 121.8%
No rule changes on record between these events
Mid-Ohio Sports Car Course Runoffs 20162016-09-191:14.920Ryan Norman · fastest of 5 · top 5 within 7.0s1:19.009Ryan Norman · fastest of 5 · top 5 within 4.7s1:30.651Tom Sloe · fastest of 22 · top 5 within 3.6s1:33.424Edward Hosni · fastest of 20 · top 5 within 1.0s+14.415squal +15.731s118.2%qual 121.0%1:37.942Alex Scaler · fastest of 41 · top 5 within 0.3s1:38.066Flinn Lazier · fastest of 38 · top 5 within 0.7s+19.057squal +23.022s124.1%qual 130.7%1:33.847Michael Galati · fastest of 25 · top 5 within 0.8s1:34.266Michael Galati · fastest of 23 · top 5 within 1.3s+15.257squal +18.927s119.3%qual 125.3%
No rule changes on record between these events
Daytona International Speedway Runoffs 20152015-09-211:47.758Tyler Hunter · fastest of 10 · top 5 within 3.7s1:48.162Tyler Hunter · fastest of 8 · top 5 within 5.3s2:01.746Tom Sloe · fastest of 22 · top 5 within 2.6s2:02.922Andy McDermid · fastest of 19 · top 5 within 2.2s+14.760squal +13.988s113.6%qual 113.0%2:21.167Roger Siebenaler · fastest of 31 · top 5 within 0.8s2:21.142Andrew Whitston · fastest of 30 · top 5 within 1.1s+32.980squal +33.409s130.5%qual 131.0%2:03.794Kip Van Steenburg · fastest of 29 · top 5 within 3.2s2:05.109Kip Van Steenburg · fastest of 28 · top 5 within 3.3s+16.947squal +16.036s115.7%qual 114.9%

By track

TrackEventsTypical % of FABestLatest
Road America4100.0%100.0%Runoffs 2020100.0%Runoffs 2026
Virginia International Raceway3100.0%2 of 3 with FA100.0%Runoffs 2019100.0%Runoffs 2022
Indianapolis Motor Speedway2100.0%100.0%Runoffs 2017100.0%Runoffs 2021
Daytona International Speedway1100.0%100.0%Runoffs 2015100.0%Runoffs 2015
Mid-Ohio Sports Car Course1100.0%100.0%Runoffs 2016100.0%Runoffs 2016
Sonoma Raceway1100.0%100.0%Runoffs 2018100.0%Runoffs 2018
About this data
Every event the class ran, at any track, oldest to newest on the chart and newest first in the table. Each point is the class's best lap as a share of FA's best on the same day: the weather, the track and its configuration cancel out, so one figure compares across tracks and years where lap times cannot. It still moves when the yardstick's own balance changes or its field thins, and an event the yardstick did not run has no point. A best from fewer than three cars is greyed. The rule changes that took effect between two events are folded between their rows.