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BoP Lab / Classes / FF

FF vs AS vs SM pace at every track

Lap times across years say as much about the weather as the class. % of FF is each class's best lap as a share of FF'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)
vsAS×B-Spec+EP+FA+FC+FE2+FF×FP+FV+FX+GT1+GT2+GTX+HP+P+P2+vsSM×SMX+SRF3+STL+STU+T1+T2+T3+T4+Show 51 inactive classes
Series
Reference class · the yardstick the % column and chart are measured against
Tracks · untick to narrow

Closest to the field: FF 100.0% of FF Rick Payne, Daytona International Speedway Runoffs 2015 race · AS 88.2% of FF James Jost, Virginia International Raceway Runoffs 2019 race · SM 97.1% of FF Elivan Goulart, Virginia International Raceway Runoffs 2019 race

1:402:002:202:4011 rule changes between Runoffs 2018 and Runoffs 201911 ▾22 rule changes between Runoffs 2019 and Runoffs 202022 ▾18 rule changes between Runoffs 2020 and Runoffs 202118 ▾10 rule changes between Runoffs 2021 and Runoffs 202210 ▾6 rule changes between Runoffs 2022 and Runoffs 20236 ▾17 rule changes between Runoffs 2023 and Runoffs 202417 ▾19 rule changes between Runoffs 2024 and Runoffs 202519 ▾17 rule changes between Runoffs 2025 and Runoffs 202617 ▾FF race best at Runoffs 2015: 2:03.383 (Rick Payne)FF race best at Runoffs 2016: 1:30.133 (Neil Verhagen)FF race best at Runoffs 2017: 1:44.524 (Jonathon Kotyk)FF race best at Runoffs 2018: 1:42.049 (Jonathon Kotyk)FF race best at Runoffs 2019: 2:20.474 (Jonathan Kotyk)FF race best at Runoffs 2020: 2:24.268 (Jeffrey Bartz)FF race best at Runoffs 2021: 1:55.676 (Jonathan Kotyk)FF race best at Runoffs 2022: 2:18.358 (Jonathan Kotyk)FF race best at Runoffs 2023: 2:00.583 (Jonathan Kotyk)FF race best at Runoffs 2024: 2:22.057 (Sebastian Mateo Naranjo)FF race best at Runoffs 2025: 2:25.541 (Calvin Kautz)FF race best at Runoffs 2026: 2:23.686 (Nathan Down)FF qualifying best at Runoffs 2015: 2:02.489 (Tim Kautz)FF qualifying best at Runoffs 2016: 1:29.213 (Neil Verhagen)FF qualifying best at Runoffs 2017: 1:44.601 (Zach Holden)FF qualifying best at Runoffs 2018: 1:41.612 (Jonathon Kotyk)FF qualifying best at Runoffs 2019: 1:59.563 (Tyler O'Connor)FF qualifying best at Runoffs 2020: 2:22.916 (Simon Sikes)FF qualifying best at Runoffs 2021: 1:44.359 (Jonathan Kotyk)FF qualifying best at Runoffs 2022: 1:59.215 (Jonathan Kotyk)FF qualifying best at Runoffs 2023: 1:59.249 (Nolan Allaer)FF qualifying best at Runoffs 2024: 2:22.552 (Calvin Kautz)FF qualifying best at Runoffs 2025: 2:24.905 (Jonathan Kotyk)FF qualifying best at Runoffs 2026: 2:23.047 (David Ybarra)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)SM race best at Runoffs 2015: 2:24.067 (Todd Lamb)SM race best at Runoffs 2016: 1:40.764 (Michael Carter)SM race best at Runoffs 2017: 1:59.100 (Michael Gagliardo)SM race best at Runoffs 2018: 1:55.278 (Michael Carter)SM race best at Runoffs 2019: 2:16.459 (Elivan Goulart)SM race best at Runoffs 2020: 2:43.748 (Preston Pardus)SM race best at Runoffs 2021: 1:58.837 (Brian Henderson)SM race best at Runoffs 2022: 2:19.107 (Travis Wiley)SM race best at Runoffs 2023: 2:16.229 (Julian DaCosta)SM race best at Runoffs 2024: 2:41.486 (Brett Kowalski)SM race best at Runoffs 2025: 2:44.430 (Kyle Greenhill)SM race best at Runoffs 2026: 2:42.725 (Francisco Barroso)SM qualifying best at Runoffs 2015: 2:18.661 (Andrew Carbonell)SM qualifying best at Runoffs 2016: 1:40.514 (Justin Hille)SM qualifying best at Runoffs 2017: 1:58.306 (Chris Haldeman)SM qualifying best at Runoffs 2018: 1:54.355 (Ken Sutherland)SM qualifying best at Runoffs 2019: 2:14.552 (Todd Buras)SM qualifying best at Runoffs 2020: 2:42.209 (Kyle Greenhill)SM qualifying best at Runoffs 2021: 1:57.695 (Brian Henderson)SM qualifying best at Runoffs 2022: 2:14.664 (Danny Steyn)SM qualifying best at Runoffs 2023: 2:14.986 (Danny Steyn)SM qualifying best at Runoffs 2024: 2:41.106 (Ethan Goulart)SM qualifying best at Runoffs 2025: 2:43.111 (Bobby Gossett)SM qualifying best at Runoffs 2026: 2:42.173 (Brett Kowalski)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
FFASSMsolid race · dashed qualifying · slower is lower
95%100%105%110%115%11 rule changes between Runoffs 2018 and Runoffs 201911 ▾22 rule changes between Runoffs 2019 and Runoffs 202022 ▾18 rule changes between Runoffs 2020 and Runoffs 202118 ▾10 rule changes between Runoffs 2021 and Runoffs 202210 ▾6 rule changes between Runoffs 2022 and Runoffs 20236 ▾17 rule changes between Runoffs 2023 and Runoffs 202417 ▾19 rule changes between Runoffs 2024 and Runoffs 202519 ▾17 rule changes between Runoffs 2025 and Runoffs 202617 ▾FF race best at Runoffs 2015: 100.0% of FF's (Rick Payne)FF race best at Runoffs 2016: 100.0% of FF's (Neil Verhagen)FF race best at Runoffs 2017: 100.0% of FF's (Jonathon Kotyk)FF race best at Runoffs 2018: 100.0% of FF's (Jonathon Kotyk)FF race best at Runoffs 2019: 100.0% of FF's (Jonathan Kotyk)FF race best at Runoffs 2020: 100.0% of FF's (Jeffrey Bartz)FF race best at Runoffs 2021: 100.0% of FF's (Jonathan Kotyk)FF race best at Runoffs 2022: 100.0% of FF's (Jonathan Kotyk)FF race best at Runoffs 2023: 100.0% of FF's (Jonathan Kotyk)FF race best at Runoffs 2024: 100.0% of FF's (Sebastian Mateo Naranjo)FF race best at Runoffs 2025: 100.0% of FF's (Calvin Kautz)FF race best at Runoffs 2026: 100.0% of FF's (Nathan Down)FF qualifying best at Runoffs 2015: 100.0% of FF's (Tim Kautz)FF qualifying best at Runoffs 2016: 100.0% of FF's (Neil Verhagen)FF qualifying best at Runoffs 2017: 100.0% of FF's (Zach Holden)FF qualifying best at Runoffs 2018: 100.0% of FF's (Jonathon Kotyk)FF qualifying best at Runoffs 2019: 100.0% of FF's (Tyler O'Connor)FF qualifying best at Runoffs 2020: 100.0% of FF's (Simon Sikes)FF qualifying best at Runoffs 2021: 100.0% of FF's (Jonathan Kotyk)FF qualifying best at Runoffs 2022: 100.0% of FF's (Jonathan Kotyk)FF qualifying best at Runoffs 2023: 100.0% of FF's (Nolan Allaer)FF qualifying best at Runoffs 2024: 100.0% of FF's (Calvin Kautz)FF qualifying best at Runoffs 2025: 100.0% of FF's (Jonathan Kotyk)FF qualifying best at Runoffs 2026: 100.0% of FF's (David Ybarra)AS race best at Runoffs 2015: 99.6% of FF's (Andy McDermid)AS race best at Runoffs 2016: 103.7% of FF's (Edward Hosni)AS race best at Runoffs 2017: 106.7% of FF's (Bryan Long)AS race best at Runoffs 2018: 108.1% of FF's (John Heinricy)Off the chart: AS race best at Runoffs 2019: 88.2% of FF's (James Jost)AS race best at Runoffs 2020: 102.4% of FF's (Gregory Eaton)AS race best at Runoffs 2021: 95.6% of FF's (Gregory Eaton)Off the chart: AS race best at Runoffs 2022: 90.0% of FF's (Gregory Eaton)AS race best at Runoffs 2023: 102.9% of FF's (Gregory Eaton)AS race best at Runoffs 2024: 103.1% of FF's (Gregory Eaton)AS race best at Runoffs 2025: 102.5% of FF's (Gregory Eaton)AS race best at Runoffs 2026: 103.3% of FF's (Andrew McDermid)AS qualifying best at Runoffs 2015: 99.4% of FF's (Tom Sloe)AS qualifying best at Runoffs 2016: 101.6% of FF's (Tom Sloe)AS qualifying best at Runoffs 2017: 100.6% of FF's (James Jost)AS qualifying best at Runoffs 2018: 106.1% of FF's (Andrew McDermid)AS qualifying best at Runoffs 2019: 102.8% of FF's (Gregory Eaton)AS qualifying best at Runoffs 2020: 102.9% of FF's (Gregory Eaton)AS qualifying best at Runoffs 2021: 105.8% of FF's (Drew Cattell)AS qualifying best at Runoffs 2022: 102.5% of FF's (Kurt Rezzetano)AS qualifying best at Runoffs 2023: 103.2% of FF's (Daniel Richardson)AS qualifying best at Runoffs 2024: 102.8% of FF's (Gregory Eaton)AS qualifying best at Runoffs 2025: 101.3% of FF's (Andrew McDermid)AS qualifying best at Runoffs 2026: 102.7% of FF's (Andrew McDermid)Off the chart: SM race best at Runoffs 2015: 116.8% of FF's (Todd Lamb)SM race best at Runoffs 2016: 111.8% of FF's (Michael Carter)SM race best at Runoffs 2017: 113.9% of FF's (Michael Gagliardo)SM race best at Runoffs 2018: 113.0% of FF's (Michael Carter)SM race best at Runoffs 2019: 97.1% of FF's (Elivan Goulart)SM race best at Runoffs 2020: 113.5% of FF's (Preston Pardus)SM race best at Runoffs 2021: 102.7% of FF's (Brian Henderson)SM race best at Runoffs 2022: 100.5% of FF's (Travis Wiley)SM race best at Runoffs 2023: 113.0% of FF's (Julian DaCosta)SM race best at Runoffs 2024: 113.7% of FF's (Brett Kowalski)SM race best at Runoffs 2025: 113.0% of FF's (Kyle Greenhill)SM race best at Runoffs 2026: 113.3% of FF's (Francisco Barroso)SM qualifying best at Runoffs 2015: 113.2% of FF's (Andrew Carbonell)SM qualifying best at Runoffs 2016: 112.7% of FF's (Justin Hille)SM qualifying best at Runoffs 2017: 113.1% of FF's (Chris Haldeman)SM qualifying best at Runoffs 2018: 112.5% of FF's (Ken Sutherland)SM qualifying best at Runoffs 2019: 112.5% of FF's (Todd Buras)SM qualifying best at Runoffs 2020: 113.5% of FF's (Kyle Greenhill)SM qualifying best at Runoffs 2021: 112.8% of FF's (Brian Henderson)SM qualifying best at Runoffs 2022: 113.0% of FF's (Danny Steyn)SM qualifying best at Runoffs 2023: 113.2% of FF's (Danny Steyn)SM qualifying best at Runoffs 2024: 113.0% of FF's (Ethan Goulart)SM qualifying best at Runoffs 2025: 112.6% of FF's (Bobby Gossett)SM qualifying best at Runoffs 2026: 113.4% of FF's (Brett Kowalski)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
FFASSMsolid race · dashed qualifying · each class's best lap as a share of FF's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker
EventFFASSM
Qual best Race best Trap Qual best Race best Trap vs FF % of FF Qual best Race best Trap vs FF % of FF 
Road America Runoffs 20262026-09-282:23.047David Ybarra · fastest of 20 · top 5 within 1.4s-1.858s (-1.28%)2:23.686Nathan Down · fastest of 20 · top 5 within 1.6s-1.855s (-1.27%)138.9Tazio Stefanelli+0.5 mph (+0.3%)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%)+4.785squal +3.864s103.3%qual 102.7%2:42.173Brett Kowalski · fastest of 34 · top 5 within 0.3s-0.938s (-0.58%)2:42.725Francisco Barroso · fastest of 35 · top 5 within 0.2s-1.705s (-1.04%)119.6Wyatt Couch+0.3 mph (+0.3%)+19.039squal +19.126s113.3%qual 113.4%
17 rule changes (FF: 2, AS: 13, SM: 2)2 cars added · 2 engine · 2 tyres & wheels · 2 weight · 1 induction · 1 suspension & brakes · 4 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. · FF Kent 1600 compression ratio calculation parameters reorganized: bore size and valve protrusion limits moved to separate subsections for clarity. · SM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361. · AS GM LM7 5.3L must use full prep Holley carburetor as described in 9.1.6.D.c.1, not specifically 4776. · 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. · SM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c. · 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. · AS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm. · FF clarifies alternative tire eligibility: homologated 1989 or earlier with rocker or outboard suspension all four corners; push-rod/pull-rod cars may seek approval. · AS Ford Mustang GT 94-04 Restricted Prep Engine now permits Ford Motorsport M-6250-F303 camshaft. · AS Cadillac CTS-V 04-07 Restricted Prep minimum weight drops to 3400 lbs.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 & wheelsaddedtyres & 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 & brakesfastersuspension & 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 #40532weightslowerweightAS Ford Mustang Coupe GT 05-14 Gen3 Coyote minimum weight increases from 3100 to 3400 lbs.
  • FF Clarification in FF Kent 1600 Compression Ratio Paragraph #40293wordingwordingFF Kent 1600 compression ratio calculation parameters reorganized: bore size and valve protrusion limits moved to separate subsections for clarity.
  • SM Rear Toe Link #40271wordingwordingSM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361.
  • 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.
  • AS Header Information Update for EFI Engine Build Sheets #39886engineaddedengineAS 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.
  • SM Part Number Change Request #39914otherunclearSM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c.
  • 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.
  • AS Restrictor Plate Change for Gen 2 Ford Coyote Engine #39501inductionslowerinductionAS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm.
  • FF Formula F Alternative Tire Rule Proposed Clarifications #39281tyres & wheelsaddedtyres & wheelsFF clarifies alternative tire eligibility: homologated 1989 or earlier with rocker or outboard suspension all four corners; push-rod/pull-rod cars may seek approval.
  • AS 1994 Mustang Spec Line Request #39104engineaddedengineAS Ford Mustang GT 94-04 Restricted Prep Engine now permits Ford Motorsport M-6250-F303 camshaft.
  • AS Cadillac CTS-V BOP Weight Change #38640weight -50 lbsfasterweightAS Cadillac CTS-V 04-07 Restricted Prep minimum weight drops to 3400 lbs.
Road America Runoffs 20252025-09-292:24.905Jonathan Kotyk · fastest of 17 · top 5 within 1.1s+2.353s (+1.65%)2:25.541Calvin Kautz · fastest of 16 · top 5 within 0.5s+3.484s (+2.45%)138.4Tazio Stefanelli-2.3 mph (-1.6%)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%)+3.691squal +1.887s102.5%qual 101.3%2:43.111Bobby Gossett · fastest of 32 · top 5 within 0.3s+2.005s (+1.24%)2:44.430Kyle Greenhill · fastest of 28 · top 5 within 0.3s+2.944s (+1.82%)119.3Francisco Barroso-0.6 mph (-0.5%)+18.889squal +18.206s113.0%qual 112.6%
19 rule changes (FF: 4, AS: 11, SM: 4)4 engine · 2 tyres & wheels · 2 weight · 1 cars added · 1 induction · 6 wording · 3 other · AS Ford Mustang GT 5.0 2018- minimum weight reduced to 3525 lbs. · 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. · SMX drivers must submit data acquisition files on time or face suspension and $250 fine. · SMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fines, level 2 and 4 may carry $500 fines. · 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. · FF adds rocker arm and outboard suspension cars option to use Hoosier bias ply slicks or VFF tyres; clarifies mixing rules. · SM tire marking rules clarified: one Hoosier SM 7.5 P205/50/ZR17 set per Super Tour weekend, impound after first dry session, damaged tires may be replaced with used tires only. · 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. · AS removes 'Any ECM maybe used' note from five Cadillac and Chevrolet/Pontiac V8 Restricted Prep models. · FF adds alternative tire options for older cars with rocker arm or outboard suspension: bias ply slicks or VFF radials. · 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. · SMX OE instrument cluster must stay unmodified and connected; aftermarket dash allowed if wiring only re-routed; alternate gauges now permitted; foot pedal comfort mods allowed without relocation. · FF and FC sequential gearbox weight penalty reduces from 25 lbs to 10 lbs minimum weight addition. · FF Honda Fit pistons: OEM 0.25mm oversize PN 13020-RB7-Z00 or Fast Forward PN FF800-110 now both allowed; standard diameter 73.240mm (2.8835 inches), minimum weight 198.0g.showhide
  • AS RE: Previous Letter 37695 Update #38245weight -75 lbsfasterweightAS Ford Mustang GT 5.0 2018- minimum weight reduced to 3525 lbs.
  • 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.
  • SM SMX Data Submission - Penalties #38248otheraddedSMX drivers must submit data acquisition files on time or face suspension and $250 fine.
  • SM Committee) SMX Penaly Clarification updated language #38337wordingwordingSMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fines, level 2 and 4 may carry $500 fines.
  • AS Errors and Omission #38055inductionslowerinductionAS 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.
  • FF Page 228, FF tire rule 9.1.1.10.e #38251tyres & wheelsaddedtyres & wheelsFF adds rocker arm and outboard suspension cars option to use Hoosier bias ply slicks or VFF tyres; clarifies mixing rules.
  • SM Clarify Tire Marking Regs #38005wordingwordingSM tire marking rules clarified: one Hoosier SM 7.5 P205/50/ZR17 set per Super Tour weekend, impound after first dry session, damaged tires may be replaced with used tires only.
  • 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.
  • AS Race memo #37902wordingwordingAS removes 'Any ECM maybe used' note from five Cadillac and Chevrolet/Pontiac V8 Restricted Prep models.
  • FF Formula F Proposal to Invite Older Cars Via a Tire Rule Change #37802tyres & wheelsaddedtyres & wheelsFF adds alternative tire options for older cars with rocker arm or outboard suspension: bias ply slicks or VFF radials.
  • AS Increase Coyote Engine Restrictor to 80mm #36177enginefasterengineAS Ford Mustang and Cobra Coyote engine restrictor increases to 80mm from 67mm or 64mm.
  • AS Performance Pack for 2015+ Mustang #36867enginefasterengineAS 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 #37208engineaddedengineAS LS-engine cars gain ECU freedom: CTS-V, Camaro, Firebird (70–02) and Camaro SS may use any ECM.
  • SM E&O SMX Regs 9.1.7.1.D.5.u-.w #37070wordingwordingSMX OE instrument cluster must stay unmodified and connected; aftermarket dash allowed if wiring only re-routed; alternate gauges now permitted; foot pedal comfort mods allowed without relocation.
  • FF Change FF/FC Weight with Sequential Gearbox #36651weightfasterweightFF and FC sequential gearbox weight penalty reduces from 25 lbs to 10 lbs minimum weight addition.
  • FF Alternative Oversize Honda Fit Pistons #37064engineaddedengineFF Honda Fit pistons: OEM 0.25mm oversize PN 13020-RB7-Z00 or Fast Forward PN FF800-110 now both allowed; standard diameter 73.240mm (2.8835 inches), minimum weight 198.0g.
Road America Runoffs 20242024-10-012:22.552Calvin Kautz · fastest of 13 · top 5 within 1.1s-0.364s (-0.25%)2:22.057Sebastian Mateo Naranjo · fastest of 13 · top 5 within 0.6s-2.211s (-1.53%)140.7Calvin Kautz+2.6 mph (+1.9%)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%)+4.372squal +4.026s103.1%qual 102.8%2:41.106Ethan Goulart · fastest of 49 · top 5 within 0.5s-1.103s (-0.68%)2:41.486Brett Kowalski · fastest of 43 · top 5 within 0.3s-2.262s (-1.38%)119.9Alex Bertagnoli-1.4 mph (-1.2%)+19.429squal +18.554s113.7%qual 113.0%
17 rule changes (FF: 2, AS: 11, SM: 4)5 cars added · 3 engine · 1 tyres & wheels · 3 wording · 5 other · FF EGR blanking plate rule clarified: VTEC activation valve must be retained and functioning, no modifications permitted. · AS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options. · SMX Spec MX-5 camera requirement: non-functioning recorder now will instead of may warrant penalty or disqualification. · SM and SMX must run latest AIM Data Logger Spec MX-5 ECU Protocol, effective 2024-09-01. · SMX Mazda MX-5 OE versus OEM definitions clarified in GCR section 9.1.7.1; wording change only. · SM and SMX now allow an alternate shifter bushing at the bottom of the shift lever. · AS adds 2018-23 Ford Mustang GT 5.0L at 3600 lbs, 275 tire, 60mm restrictor, optional Brembo front brakes. · 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… · FF Honda Fit gains Fast Forward oversize piston ring option PN FF800-100 as alternative to Riken or Nippon.showhide
  • FF Update to FF EGR Blanking Plate Rule #36633wordingwordingFF EGR blanking plate rule clarified: VTEC activation valve must be retained and functioning, no modifications permitted.
  • AS Mustang transmission ratios #36662otheraddedAS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options.
  • SM SMX Camera Rule Correction #36496wordingwordingSMX Spec MX-5 camera requirement: non-functioning recorder now will instead of may warrant penalty or disqualification.
  • SM Committee) AIM ECU Protocol #36556engineaddedengineSM and SMX must run latest AIM Data Logger Spec MX-5 ECU Protocol, effective 2024-09-01.
  • SM Committee) OE versus OEM Definitons #36608wordingwordingSMX Mazda MX-5 OE versus OEM definitions clarified in GCR section 9.1.7.1; wording change only.
  • SM Committee) Shifter Bushing #36611otheraddedSM and SMX now allow an alternate shifter bushing at the bottom of the shift lever.
  • 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.
  • 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 #35891engineaddedengineAS 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 & wheelsfastertyres & 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…
  • FF Honda Fit Oversize Piston Rings #35305engineaddedengineFF Honda Fit gains Fast Forward oversize piston ring option PN FF800-100 as alternative to Riken or Nippon.
Virginia International Raceway Runoffs 20232023-09-231:59.249Nolan Allaer · fastest of 8 · top 5 within 2.8s+0.034s (+0.03%)2:00.583Jonathan Kotyk · fastest of 8 · top 5 within 0.4s-17.775s (-12.85%)138.4Calvin Kautz+0.1 mph (+0.1%)2:03.082Daniel 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%)+3.537squal +3.833s102.9%qual 103.2%2:14.986Danny Steyn · fastest of 52 · top 5 within 0.1s+0.322s (+0.24%)2:16.229Julian DaCosta · fastest of 46 · top 5 within 0.3s-2.878s (-2.07%)120.3Jim Drago+1.1 mph (+0.9%)+15.646squal +15.737s113.0%qual 113.2%
6 rule changes (FF: 1, AS: 4, SM: 1)1 engine · 1 tyres & wheels · 1 weight · 2 wording · 1 other · 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. · FF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components. · SM Mazda MX-5 Miata 01-05 minimum weight rises to 2450 lbs, or 2465 with alternate bore.showhide
  • 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 & wheelsfastertyres & 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.
  • FF Add Fast Forward Part Numbers for Honda Fit Engine #33752engineaddedengineFF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components.
  • SM BOP for NB1 and NB2 #32309weightslowerweightSM Mazda MX-5 Miata 01-05 minimum weight rises to 2450 lbs, or 2465 with alternate bore.
Virginia International Raceway Runoffs 20222022-09-241:59.215Jonathan Kotyk · fastest of 13 · top 5 within 1.2s-0.348s (-0.29%)2:18.358Jonathan Kotyk · fastest of 12 · top 5 within 2.4s-2.116s (-1.51%)138.3Tim Kautz+2.2 mph (+1.6%)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%)-13.780squal +2.947s90.0%qual 102.5%2:14.664Danny Steyn · fastest of 60 · top 5 within 0.2s+0.112s (+0.08%)2:19.107Travis Wiley · fastest of 58 · top 5 within 0.9s+2.648s (+1.94%)119.2Jonathan Neudorf-0.6 mph (-0.5%)+0.749squal +15.449s100.5%qual 113.0%
10 rule changes (AS: 9, SM: 1)2 cars added · 2 weight · 1 engine · 1 tyres & wheels · 3 wording · 1 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. · AS Cadillac CTS-V 6.0L V8 Restricted Prep removes 295 tire size 50 lb penalty. · SM Majors must run authorized Penske shock and mount; Regional competitors not required until further evaluation. · 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. · 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.showhide
  • AS Request to add Hoosier W2 #33031tyres & wheelsaddedtyres & 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.
  • AS Request CTS-V Spec Line Error Correction #30242weightfasterweightAS Cadillac CTS-V 6.0L V8 Restricted Prep removes 295 tire size 50 lb penalty.
  • SM Update GCR Section 9.1.7.3.A.1. #32217wordingwordingSM Majors must run authorized Penske shock and mount; Regional competitors not required until further evaluation.
  • 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 addedremovedcars 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 #31851engineaddedengineAS Camaro, Firebird, Mustang full prep engines: alternate GM and Ford Performance cylinder heads permitted regionally with Allstar restrictor ALL26180.
  • 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 #30881weightslowerweightAS Pontiac GTO 04-06 Restricted Prep minimum weight rises: LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tires.
Indianapolis Motor Speedway Runoffs 20212021-09-251:44.359Jonathan Kotyk · fastest of 24 · top 5 within 1.1s-0.242s (-0.23%)1:55.676Jonathan Kotyk · fastest of 23 · top 5 within 1.8s+11.152s (+10.67%)141.6Nicholas Sheppard1:50.427Drew 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-5.070squal +6.068s95.6%qual 105.8%1:57.695Brian Henderson · fastest of 90 · top 5 within 0.5s-0.611s (-0.52%)1:58.837Brian Henderson · fastest of 88 · top 5 within 0.3s-0.263s (-0.22%)119.8Kyle Greenhill+3.161squal +13.336s102.7%qual 112.8%
18 rule changes (FF: 3, AS: 14, SM: 1)5 cars added · 3 weight · 2 engine · 6 wording · 2 other · 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. · FF block relief permitted only as needed to fit an allowed crankshaft. · SM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture. · 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. · 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. · 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. · FF class cylinder head now permits optional coolant bleed line pipe thread fitting to swirl tower. · FF Honda LC1 ECU supplied by HPD is permitted effective 12/1/2020 with HPD lambda sensor.showhide
  • AS Request CTS-V Spec Line Error Correction #30242weightfasterweightAS 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 #30595enginefasterengineAS 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 lbsslowerweightAS Camaro, Firebird, Mustang, and Capri all gain 50 lbs minimum weight across seven model year variants.
  • FF Kent crankshaft clarification #30426wordingwordingFF block relief permitted only as needed to fit an allowed crankshaft.
  • SM Updates - Obsolete Parts & BOP Parts #30438wordingaddedSM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture.
  • AS AS Mustang LP 4.6 3V Classification Transmission Request #29886enginefasterengineAS 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.
  • 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 #29759weightfasterweightAS 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.
  • 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.
  • FF Allow Optional Coolant Bleed Line to Correct a Known Problem #29673otheraddedFF class cylinder head now permits optional coolant bleed line pipe thread fitting to swirl tower.
  • FF Clarification regarding Honda LC1 ECU implementation date #29684wordingwordingFF Honda LC1 ECU supplied by HPD is permitted effective 12/1/2020 with HPD lambda sensor.
Road America Runoffs 20202020-10-022:22.916Simon Sikes · fastest of 14 · top 5 within 1.6s2:24.268Jeffrey Bartz · fastest of 14 · top 5 within 0.4s138.1Jeffrey Bartz2:27.045Gregory Eaton · fastest of 18 · top 5 within 0.6s2:27.668Gregory Eaton · fastest of 15 · top 5 within 1.5s149.2Gregory Eaton+3.400squal +4.129s102.4%qual 102.9%2:42.209Kyle Greenhill · fastest of 77 · top 5 within 0.5s2:43.748Preston Pardus · fastest of 75 · top 5 within 1.0s121.3Kyle Greenhill+19.480squal +19.293s113.5%qual 113.5%
22 rule changes (FF: 4, AS: 16, SM: 2)5 engine · 2 cars added · 2 suspension & brakes · 2 weight · 1 aero · 1 tyres & wheels · 8 wording · 1 other · SM allows aftermarket radiators in original location with stock OEM cooling fan, and permits 1990-1997 cars to install upper radiator seal NA75-50-OK7A. · 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. · FF Honda LC1 ECU implementation date clarified to pending, contingent on SCCA receiving sufficient support materials. · SM rear brake caliper may use single bracket under upper retaining bolt head to prevent pin failure. · 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 · FF Kent Engine alternator becomes optional instead of not required. · FF permits HPD LC1 ECU with lambda sensor; E1 ECU no longer supported but existing units may continue. · FF rain tyres now allow Hoosier W3 Radial 185/60R13 front and 205/60R13 rear. · 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.showhide
  • SM Radiator E&O Clarifications #29294wordingwordingSM allows aftermarket radiators in original location with stock OEM cooling fan, and permits 1990-1997 cars to install upper radiator seal NA75-50-OK7A.
  • AS Dodge Challenger AS Spec Line Clarification #28698engineslowerengineAS 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.
  • FF Clarification regarding Honda LC1 ECU implementation #29135wordingwordingFF Honda LC1 ECU implementation date clarified to pending, contingent on SCCA receiving sufficient support materials.
  • SM Modifications to prevent failures of Rear Brake Caliper Pin #28953suspension & brakessuspension & brakesSM rear brake caliper may use single bracket under upper retaining bolt head to prevent pin failure.
  • 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 #27908engineaddedengineAS Restricted Prep 4.6 3V now permits conversion to 2 valve configuration.
  • AS Request for 2005-2009 Restricted Prep 4.6 3V Parts #27909engineaddedengineAS 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
  • AS weight adjustments for 2020 season #28785weight -50 lbs
  • FF E&O FF Kent Engine alternator language #28204engineaddedengineFF Kent Engine alternator becomes optional instead of not required.
  • FF Honda Racing HPD low cost ECU proposal #27563engineaddedengineFF permits HPD LC1 ECU with lambda sensor; E1 ECU no longer supported but existing units may continue.
  • FF Update rain tire designation #28443tyres & wheelsaddedtyres & wheelsFF rain tyres now allow Hoosier W3 Radial 185/60R13 front and 205/60R13 rear.
  • AS Rear Trailing Arms #28007suspension & brakesaddedsuspension & 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 #28010weightfasterweightAS 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.
Virginia International Raceway Runoffs 20192019-10-051:59.563Tyler O'Connor · fastest of 14 · top 5 within 1.4s2:20.474Jonathan Kotyk · fastest of 14 · top 5 within 6.3s136.2Derek Ketchie2:02.938Gregory Eaton · fastest of 17 · top 5 within 0.8s2:03.900James Jost · fastest of 16 · top 5 within 2.1s153.9James Jost-16.574squal +3.375s88.2%qual 102.8%2:14.552Todd Buras · fastest of 60 · top 5 within 0.2s2:16.459Elivan Goulart · fastest of 56 · top 5 within 0.4s119.8Jim Drago-4.015squal +14.989s97.1%qual 112.5%
11 rule changes (FF: 3, AS: 4, SM: 4)2 cars added · 1 aero · 1 engine · 1 weight · 4 wording · 2 other · AS Spec Mustang (SMG) added as Restricted Prep class. · AS class ride height minimum clarified: five inches measured at rocker panel, excluding seams and stock effects. · AS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450. · SM fuel pump and filter now permitted as Mazda or OEM equivalent part. · AS adds Spec Mustang SMG classification with 107.1 wheelbase, 3.73 gears, 355mm front and 300mm rear brakes. · FF Honda Fit cylinder honing increased to 73.315mm and oversize pistons PN 13020-RB7-Z00 now permitted with matching ring packs. · FF intake manifold thermal wrap now permitted if easily removable for inspection; no coating allowed. · FF clarifies coolant and oil catch tank capacity requirements: coolant minimum one U.S. pint, oil minimum one U.S. quart per system. · SM allows factory Mazda ECU and injector harnesses (P/N 0000-10-020E-99, 0000-10-080D-99) on 1999–2000 model year cars, unmodified. · SM electrical rules reorganized and clarified; alternator now externally regulated only by OEM ECU or master kill switch; harness repair by splicing permitted. · SM tire tread protrusion language removed from GCR 9.1.7.C.5.showhide
  • AS Request to add SMG to 9.1.6.B.1 AS Intent #27140cars addedaddedAS Spec Mustang (SMG) added as Restricted Prep class.
  • AS Request Ride Height Clarification #26598wordingwordingAS class ride height minimum clarified: five inches measured at rocker panel, excluding seams and stock effects.
  • AS Request to Revert to 2017 Weights #25885weightfasterweightAS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450.
  • SM Request to allow aftermarket fuel filters. #26370otheraddedSM fuel pump and filter now permitted as Mazda or OEM equivalent part.
  • 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.
  • FF Request for Oversize Honda Fit Pistons #25810enginefasterengineFF Honda Fit cylinder honing increased to 73.315mm and oversize pistons PN 13020-RB7-Z00 now permitted with matching ring packs.
  • FF Heat Shield - Fit Intake #26102aeroaddedaeroFF intake manifold thermal wrap now permitted if easily removable for inspection; no coating allowed.
  • FF Request catch cans/tanks clarification #26158wordingwordingFF clarifies coolant and oil catch tank capacity requirements: coolant minimum one U.S. pint, oil minimum one U.S. quart per system.
  • SM Request 99-00 replacement Wire harnesses #25602otheraddedSM allows factory Mazda ECU and injector harnesses (P/N 0000-10-020E-99, 0000-10-080D-99) on 1999–2000 model year cars, unmodified.
  • SM Organize and Clarify 9.1.7.C.1.o. #25913wordingwordingSM electrical rules reorganized and clarified; alternator now externally regulated only by OEM ECU or master kill switch; harness repair by splicing permitted.
  • SM Strike Tire Tread Language #26123wordingremovedSM tire tread protrusion language removed from GCR 9.1.7.C.5.
Sonoma Raceway Runoffs 20182018-10-101:41.612Jonathon Kotyk · fastest of 22 · top 5 within 1.7s1:42.049Jonathon Kotyk · fastest of 22 · top 5 within 1.3s115.7Denny Renfrow1:47.782Andrew McDermid · fastest of 12 · top 5 within 1.9s1:50.345John Heinricy · fastest of 10 · top 5 within 2.3s105.0Kevin Fandozzi+8.296squal +6.170s108.1%qual 106.1%1:54.355Ken Sutherland · fastest of 48 · top 5 within 0.7s1:55.278Michael Carter · fastest of 48 · top 5 within 0.3s102.2Danny Steyn+13.229squal +12.743s113.0%qual 112.5%
No rule changes on record between these events
Indianapolis Motor Speedway Runoffs 20172017-09-251:44.601Zach Holden · fastest of 36 · top 5 within 1.2s1:44.524Jonathon Kotyk · fastest of 36 · top 5 within 0.5s1:45.220James Jost · fastest of 29 · top 5 within 6.7s1:51.507Bryan Long · fastest of 28 · top 5 within 0.9s+6.983squal +0.619s106.7%qual 100.6%1:58.306Chris Haldeman · fastest of 86 · top 5 within 0.5s1:59.100Michael Gagliardo · fastest of 83 · top 5 within 0.6s+14.576squal +13.705s113.9%qual 113.1%
No rule changes on record between these events
Mid-Ohio Sports Car Course Runoffs 20162016-09-191:29.213Neil Verhagen · fastest of 14 · top 5 within 2.1s1:30.133Neil Verhagen · fastest of 14 · top 5 within 1.4s1:30.651Tom Sloe · fastest of 22 · top 5 within 3.6s1:33.424Edward Hosni · fastest of 20 · top 5 within 1.0s+3.291squal +1.438s103.7%qual 101.6%1:40.514Justin Hille · fastest of 45 · top 5 within 0.3s1:40.764Michael Carter · fastest of 44 · top 5 within 0.3s+10.631squal +11.301s111.8%qual 112.7%
No rule changes on record between these events
Daytona International Speedway Runoffs 20152015-09-212:02.489Tim Kautz · fastest of 25 · top 5 within 1.1s2:03.383Rick Payne · fastest of 22 · top 5 within 0.8s2:01.746Tom Sloe · fastest of 22 · top 5 within 2.6s2:02.922Andy McDermid · fastest of 19 · top 5 within 2.2s-0.461squal -0.743s99.6%qual 99.4%2:18.661Andrew Carbonell · fastest of 62 · top 5 within 0.6s2:24.067Todd Lamb · fastest of 59 · top 5 within 0.8s+20.684squal +16.172s116.8%qual 113.2%

By track

TrackEvents Typical % of FF Best Latest 
Road America4100.0%100.0%Runoffs 2020100.0%Runoffs 2026
Virginia International Raceway3100.0%100.0%Runoffs 2019100.0%Runoffs 2023
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 FF's best on the same day: the weather and the day cancel out, so one figure compares across years where lap times cannot; a class that suits one track more than another still reads differently there. 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.