Lap times across years say as much about the weather as the class. % of GT3 is each class's best lap as a share of GT3'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.
Closest to the field:GT3 100.0% of GT3 Joe Kristensen, Daytona International Speedway Runoffs 2015 race · FB 87.8% of GT3 J R Osborne, Sonoma Raceway Runoffs 2018 qualifying · FM 94.8% of GT3 Jacob Loomis, Mid-Ohio Sports Car Course Runoffs 2016 qualifying · AS 86.3% of GT3 Gregory Eaton, Virginia International Raceway Runoffs 2022 race
GT3FBFMASsolid race · dashed qualifying · slower is lower
GT3FBFMASsolid race · dashed qualifying · each class's best lap as a share of GT3's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker
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%)
15 rule changes (GT3: 2, AS: 13)3 cars added · 2 engine · 2 suspension & brakes · 2 weight · 1 induction · 1 tyres & wheels · 2 wording · 2 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. · 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. · AS Spec Lines reorganized for 2026; detailed chassis, engine, weight, wheelbase, tire and brake specifications moved to main rules and engine build sheets. · GT3U class removed from GCR; GT3U cars now compete in STU. · 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. · GT3U cars must meet 3.0" minimum ride height on frame rails and 2.0" on front spoiler and splitter. · 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.
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.
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.
GT3 Remove GT3U from GCR as it is now in STU #39862cars addedremovedcars addedGT3U class removed from GCR; GT3U cars now compete in STU.
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.
GT3 GT3U Ride Height #39637suspension & brakesaddedsuspension & brakesGT3U cars must meet 3.0" minimum ride height on frame rails and 2.0" on front spoiler and splitter.
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.
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%)
20 rule changes (GT3: 9, AS: 11)8 weight · 3 engine · 2 cars added · 1 induction · 4 wording · 2 other · GT3U cars with 15x7 wheels gain 225 lbs; optional 15x9 wheels add 1.5% weight, 18x9 wheels add 3.0%. TCR cars now ineligible for GT3/GT3U. · 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. · 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. · GT3U with 15"x7" wheels and 225 section tires now runs plus 225 lbs instead of plus 150 lbs; wheel and weight options clarified. · 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. · 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. · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof height limit. · GT3 VW Fun Cup Beetle exempted from 150 lbs consolidation add-on weight. · GT3 Pontiac LE5 Ecotech minimum weight drops 150 lbs to 2195. · GT3 Mazda 13B Bridgeport and Peripheral Port minimum weights drop to 2275 lbs. · GT3 adds Nissan MR20DE DOHC engine, 1997cc, 32mm SIR, 2060 lbs minimum weight. · GT3 Mazda 13B minimum weight drops from 2350 to 2175 lbs; disfranchised GT2 baseline now 2175 lbs. · GT3 Mazda 12A peripheral port minimum weight reduced 200 lbs to 2100.showhide
GT3 Declassify TCR Cars from GT3/GT3U #38569weightslowerweightGT3U cars with 15x7 wheels gain 225 lbs; optional 15x9 wheels add 1.5% weight, 18x9 wheels add 3.0%. TCR cars now ineligible for GT3/GT3U.
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.
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.
GT3 Clarification of GT3U #38266weightslowerweightGT3U with 15"x7" wheels and 225 section tires now runs plus 225 lbs instead of plus 150 lbs; wheel and weight options clarified.
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.
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.
GT3 Correct language regarding OEM Areo Devices #37137wordingwordingTA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof height limit.
GT3 VW Funcap weight #37217weightfasterweightGT3 VW Fun Cup Beetle exempted from 150 lbs consolidation add-on weight.
GT3 Pontiac Weight and Chassis Adjustment Request #36938weight -150 lbsfasterweightGT3 Pontiac LE5 Ecotech minimum weight drops 150 lbs to 2195.
GT3 GCR GT3 Disfranchised GT2 #36291weight -75 lbsfasterweightGT3 Mazda 13B Bridgeport and Peripheral Port minimum weights drop to 2275 lbs.
2:22.108Tony Ave · fastest of 13 · top 5 within 3.7s+0.226s (+0.16%)
2:22.863Tony Ave · fastest of 13 · top 5 within 3.3s-1.368s (-0.95%)
151.2Jeff Dernehl+1.8 mph (+1.2%)
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%)
+3.566squal +4.470s
102.5%qual 103.1%
41 rule changes (GT3: 30, AS: 11)11 cars added · 8 weight · 5 engine · 3 aero · 2 tyres & wheels · 1 induction · 6 wording · 5 other · AS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options. · GT3 Mazda 3TC added to TCR spec line at 2950 lbs, must conform to 2024 TC Car specs. · GT3 adds Nissan 1200 (B110) 70–73, must use GT3-classified engine or request alternate Nissan engine. · GT3-TCR Honda Civic Type R SEQ minimum weight raised to 3210 lbs; Hyundai I30N and VW GTI SEQ reduced 100 lbs each. · GT3 Pontiac Sunfire GT weight reduction note changes from 150 to 75. · GT3 Mazda MZR removes second DOHC option, fuel induction now unrestricted. · AS adds 2018-23 Ford Mustang GT 5.0L at 3600 lbs, 275 tire, 60mm restrictor, optional Brembo front brakes. · GT3 cars may run +1mm SIR above spec with 175 lb weight penalty. · GT3 turbocharged 1401–1850 cc four-valve engine with 34 mm restrictor drops to 2250 lbs minimum weight. · 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. · GT2-ST Acura NSX minimum weight rises to 3000 lbs, restrictor increases to 45mm TIR. · GT3 Ford Duratech engine now allows hood bulge with no openings. · GT3 Acura K20A RSX body adds 75 lbs for disenfranchised GT2 entries. · GT3 Toyota 4Y engine added: 2237cc OHV, 2030 lbs minimum weight, unrestricted fuel induction. · GT3 Toyota model designation changed from DR86 to GR86. · GT3 Honda K20C1 and K24 engines have spec line designations clarified, removing bore and displacement references. · GT3 Mazda spec line reorganized: model column heading, 323 and 626 designations, weight figures updated. · 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… · GT3 Miata Turbo restrictor increases to 35 mm, minimum weight rises to 2350 lbs. · GT1-GTX rear blade spoiler: angle 50–75°, max 59.0 wide by 5.0 high inches; total area limit removed. · GT1, GT2, GT3, GTL, GTX Direct Injection now permitted if original equipment. · GT3 Toyota FA24D 2387cc DOHC engine added, 2195 lbs, direct injection permitted. · GT2 Nissan and GT3 Mazda, Mitsubishi 4G93, Nissan QR25DE/DD, QE25DE/DD now permit Direct Injection per 9.1.2.F.7.5.E. · GT3 Nissan QR25DE/DD spec line edit appears corrupted; text unreadable. · GT3 Mazda RX7 12A, 13B Bridgeport, 13B Peripheral Port: disenfranchised GT2 cars add 75 lbs. · GT3 Mazda BP4W turbocharged engine minimum weight reduced 100 lbs to 1960. · GT3 Mazda 13B peripheral port minimum weight reduced to 2100 lbs. · Toyota GR 86 DR86 2021–2024 added to GT3 as rear-wheel-drive coupe, 101.3 in wheelbase. · GT3 Toyota 3S bore increases to 86.0 mm, stroke decreases to 86.0 mm. · GT3 Toyota 3S DOHC engine classified at 1998 cc, 1960 lbs minimum weight, unrestricted fuel induction. · GT3 2.0L SIR engines remove 32mm restrictor option and 2195 lbs unrestricted weight allowance for all listed makes. · GTL spec lines moved contiguous with GT2 and GT3; GTA category and specs renumbered behind GTL; P2 engine tables reorganised with restrictor and weight specifications clarified. · GT3-TCR Audi RS3 LMS, Honda Civic Type R, Hyundai i30 N, VW Golf GTi must use 200 tread wear any DOT tires. · GT3 Honda B20 engine classified for use; 1973cc DOHC with 84mm bore, 89mm stroke, aluminum head.showhide
AS Mustang transmission ratios #36662otheraddedAS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options.
GT3 2024 Mazda 3 TC request for GT3 #36517cars addedaddedGT3 Mazda 3TC added to TCR spec line at 2950 lbs, must conform to 2024 TC Car specs.
GT3 Adding Datsun B110 to List of Approved Cars #36198cars addedaddedGT3 adds Nissan 1200 (B110) 70–73, must use GT3-classified engine or request alternate Nissan engine.
GT3 Honda Civic Type R TCR Weight Reduction Request #36550weightslowerweightGT3-TCR Honda Civic Type R SEQ minimum weight raised to 3210 lbs; Hyundai I30N and VW GTI SEQ reduced 100 lbs each.
GT3 Correct missed Disenfranchised weight reduction #36237wordingunclearGT3 Pontiac Sunfire GT weight reduction note changes from 150 to 75.
GT3 errors & omissions on GT3 Mazda MZR spec lines #36241wordingunclearGT3 Mazda MZR removes second DOHC option, fuel induction now unrestricted.
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.
GT3 GT3 +1mm SIR add 175lbs. In #36098aerosloweraeroGT3 cars may run +1mm SIR above spec with 175 lb weight penalty.
GT3 Revised GT3 Built Turbocharged chart #36100weightfasterweightGT3 turbocharged 1401–1850 cc four-valve engine with 34 mm restrictor drops to 2250 lbs minimum weight.
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.
GT3 Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslowerweightGT2-ST Acura NSX minimum weight rises to 3000 lbs, restrictor increases to 45mm TIR.
GT3 Mazda MZR Engines #35753aeroaddedaeroGT3 Ford Duratech engine now allows hood bulge with no openings.
GT3 Disenfranchised GT2 Acura RSX to Run GT3 #35773weightslowerweightGT3 Acura K20A RSX body adds 75 lbs for disenfranchised GT2 entries.
GT3 Toyota 4Y Engine Request #35885cars addedaddedGT3 Toyota 4Y engine added: 2237cc OHV, 2030 lbs minimum weight, unrestricted fuel induction.
GT3 GT3 spec lines clean-up #36008wordingwordingGT3 Toyota model designation changed from DR86 to GR86.
GT3 GT3 Honda spec line clean-up x 2 #36009wordingwordingGT3 Honda K20C1 and K24 engines have spec line designations clarified, removing bore and displacement references.
GT3 GT3 Mazda spec line clean-up x2 #36010wordingunclearGT3 Mazda spec line reorganized: model column heading, 323 and 626 designations, weight figures updated.
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…
GT3 Miata Turbo Clarification #35386weight +100 lbsslowerweightGT3 Miata Turbo restrictor increases to 35 mm, minimum weight rises to 2350 lbs.
GT3 Rear Blade Spoiler Clarification #35261aeroaeroGT1-GTX rear blade spoiler: angle 50–75°, max 59.0 wide by 5.0 high inches; total area limit removed.
GT3 GT Direct Injection allowance and rules #35437engineaddedengineGT1, GT2, GT3, GTL, GTX Direct Injection now permitted if original equipment.
GT3 Request to Include Toyota FA24D Engine for use in GT3 #35199cars addedaddedGT3 Toyota FA24D 2387cc DOHC engine added, 2195 lbs, direct injection permitted.
GT3 GT2/3 remove Direction Injection not allowed in Spec line notes #35439engineaddedengineGT2 Nissan and GT3 Mazda, Mitsubishi 4G93, Nissan QR25DE/DD, QE25DE/DD now permit Direct Injection per 9.1.2.F.7.5.E.
GT3 Edit GT3 Nissan QR25DE/DD spec line #35442otherunclearGT3 Nissan QR25DE/DD spec line edit appears corrupted; text unreadable.
GT3 Turbo Help #35042weight -100 lbsfasterweightGT3 Mazda BP4W turbocharged engine minimum weight reduced 100 lbs to 1960.
GT3 Competition Adjustment Request for 13B Peripheral Port #35100weight -100 lbsfasterweightGT3 Mazda 13B peripheral port minimum weight reduced to 2100 lbs.
GT3 Request to Include Toyota GR 86 in GT3 #35197cars addedaddedToyota GR 86 DR86 2021–2024 added to GT3 as rear-wheel-drive coupe, 101.3 in wheelbase.
GT3 Fastrack Toyota 3S Correction #35258engineunclearGT3 Toyota 3S bore increases to 86.0 mm, stroke decreases to 86.0 mm.
GT3 Toyota Engine Classification Request #35019engineaddedengineGT3 Toyota 3S DOHC engine classified at 1998 cc, 1960 lbs minimum weight, unrestricted fuel induction.
GT3 GT3 2.0L SIR & weight #35171inductionslowerinductionGT3 2.0L SIR engines remove 32mm restrictor option and 2195 lbs unrestricted weight allowance for all listed makes.
GT3 Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules #34453wordingwordingGTL spec lines moved contiguous with GT2 and GT3; GTA category and specs renumbered behind GTL; P2 engine tables reorganised with restrictor and weight specifications clarified.
GT3 GT3 TCR 200 TW tires #34993tyres & wheelstyres & wheelsGT3-TCR Audi RS3 LMS, Honda Civic Type R, Hyundai i30 N, VW Golf GTi must use 200 tread wear any DOT tires.
GT3 Classify Honda B20 engine in GT3 CRX #34781cars addedaddedGT3 Honda B20 engine classified for use; 1973cc DOHC with 84mm bore, 89mm stroke, aluminum head.
1:58.065Tony Ave · fastest of 9 · top 5 within 3.8s+0.930s (+0.79%)
1:59.872Tony Ave · fastest of 8 · top 5 within 3.9s-24.475s (-16.96%)
145.8Jeff Dernehl-3.6 mph (-2.4%)
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%)
+4.248squal +5.017s
103.5%qual 104.2%
14 rule changes (GT3: 10, AS: 4)3 cars added · 2 engine · 2 tyres & wheels · 1 induction · 4 wording · 2 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. · GT3 allows 15" American Racer 23.5-10.0-15 bias ply tires without weight penalty. · Fields Cardinal V8 added to GT1 with Ford V8 engine, 4.9L, 2100 lbs, fuel injection. · GT3 Nissan VG30 engine removed from class. · GT3 normally aspirated cars may now use chokes instead of SIRs, same size as listed SIR, one per carburetor barrel. · GT3 2.0L 4-valve non-turbo engines may run unrestricted at 2060 lbs minimum weight. · GT3 Mazda BP4W Turbocharged OEM engine added, 1839cc, 2060 lbs, with 34mm TIR and IHI RHF5 VJ35 turbo. · GT2 TA2 and GTA throttle body part numbers updated to GM 12570790 or Edelbrock 33869/3870. · GT3 Nissan SR20VET turbo ECU changes from stock only to open, enabling tuning. · GT3 adds 84-87 Honda Civic 3dr FWD, 86.6 in wheelbase, hood bulge allowed. · GT3 turbo maximum engine displacement clarified to 1,401-1,850 cc.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.
GT3 Addendum to letter 33913, GT3 DOT tires. #34627tyres & wheelsfastertyres & wheelsGT3 allows 15" American Racer 23.5-10.0-15 bias ply tires without weight penalty.
GT3 Please classify Fields Cardinal V8 #33784cars addedaddedFields Cardinal V8 added to GT1 with Ford V8 engine, 4.9L, 2100 lbs, fuel injection.
GT3 Remove Nissan VG30 engine from GT3 #33609engineremovedengineGT3 Nissan VG30 engine removed from class.
GT3 GT3 Choke option effective 1-01-2023 #33669inductionaddedinductionGT3 normally aspirated cars may now use chokes instead of SIRs, same size as listed SIR, one per carburetor barrel.
GT3 GT3 2.0L choke/weight option #33670otheraddedGT3 2.0L 4-valve non-turbo engines may run unrestricted at 2060 lbs minimum weight.
GT3 Turbocharged Engine Rules #33145cars addedaddedGT3 Mazda BP4W Turbocharged OEM engine added, 1839cc, 2060 lbs, with 34mm TIR and IHI RHF5 VJ35 turbo.
GT3 GT2 (TA2)/GTA Part Number Update #33315wordingwordingGT2 TA2 and GTA throttle body part numbers updated to GM 12570790 or Edelbrock 33869/3870.
GT3 GT3 Nissian SR20VET unrestricted ECU change #33432enginefasterengineGT3 Nissan SR20VET turbo ECU changes from stock only to open, enabling tuning.
1:57.135Jeff Dernehl · fastest of 13 · top 5 within 3.2s-1.059s (-0.90%)
2:24.347Tony Ave · fastest of 12 · top 5 within 8.2s+25.302s (+21.25%)
149.5Jeff Dernehl-0.2 mph (-0.1%)
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%)
-19.769squal +5.027s
86.3%qual 104.3%
26 rule changes (GT3: 17, AS: 9)12 cars added · 3 engine · 3 weight · 2 tyres & wheels · 5 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. · GT1, GT2, GT3, GTL, GTX tail lights may now be original style or custom panel graphic with functioning red LED brake lamps. · GT3 adds Nissan SR20VET Limited Prep-Turbocharged OEM engine, 1998cc, 2060 lbs, Garrett GT2560LS turbo only. · AS Cadillac CTS-V 6.0L V8 Restricted Prep removes 295 tire size 50 lb penalty. · GT3 Fiat 124 Spider model name corrected from Pininfarina to Pininfarina Spider. · GT3 Fiat 124 Spider Pininfarina classified with body style, drive-line, and wheelbase specifications. · GT3 adds 17x9 wheels with 3% weight penalty, 18" wheels with 5% penalty down from 8%, and 13" brake rotors. · GT3-TCR Audi RS3 SEQ/DSG, Honda Civic, Hyundai i30N, VW Golf GTI SEQ power cut to 90%; weights up 2–54 lbs; VW Golf GTI DSG to 97.5%. · GT3 Ginetta G40 classified with Mazda MZR 1999cc at 2060 lbs or Ford Duratec 2260cc at 2195 lbs, both 32mm SIR, 5-speed only. · GT3 Mazda MZR 1999cc DOHC newly classified with 2195 lbs minimum weight, unrestricted fuel induction. · GT3 Volvo S60 2000-2009 four-door sports coupe, front-wheel drive, 106.9 in wheelbase, newly classified. · GT3 2.0L 4V engines may run unrestricted at 2195 lbs minimum weight. · GT3 wing wording corrected; single element airfoil maximum chord length stays 10.75 inches. · GT3 adds Fiat Spider 2000, years 79-81, RWD, 89.76" wheelbase. · GT3 adds Fiat X-19, years 72-89. · 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. · GT3 Fun Cup Beetle Sealed minimum weight drops 210 lbs, to 1850. · GT3 adds TCR cars: Audi RS3 LMS, Honda Civic Type R, Hyundai i30N, Volkswagen Golf GTI at 3100–3200 lbs with 200 tread wear tires. · GT3 Ford Cortina GT 1964-1968 added to classified cars list. · 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. · GT3 Volkswagen Fun Cup Beetle EVO3 classified, sealed SOHC 1984cc engine, 2060 lbs minimum weight.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.
GT3 Tail lights on all GT category race cars. #32799wordingwordingGT1, GT2, GT3, GTL, GTX tail lights may now be original style or custom panel graphic with functioning red LED brake lamps.
GT3 Correct Model GT3 - Fiat #32776wordingwordingGT3 Fiat 124 Spider model name corrected from Pininfarina to Pininfarina Spider.
GT3 Correct Fiat Spider Years #32149cars addedaddedGT3 Fiat 124 Spider Pininfarina classified with body style, drive-line, and wheelbase specifications.
GT3 wheel size addition #32247tyres & wheelsfastertyres & wheelsGT3 adds 17x9 wheels with 3% weight penalty, 18" wheels with 5% penalty down from 8%, and 13" brake rotors.
GT3 GT3 TCR Car Feedback #31677engine +2 lbsslowerengineGT3-TCR Audi RS3 SEQ/DSG, Honda Civic, Hyundai i30N, VW Golf GTI SEQ power cut to 90%; weights up 2–54 lbs; VW Golf GTI DSG to 97.5%.
GT3 Request to Classify Ginetta G40 in GT3 #31598cars addedaddedGT3 Ginetta G40 classified with Mazda MZR 1999cc at 2060 lbs or Ford Duratec 2260cc at 2195 lbs, both 32mm SIR, 5-speed only.
GT3 Volvo S60 in GT3 #31970cars addedaddedGT3 Volvo S60 2000-2009 four-door sports coupe, front-wheel drive, 106.9 in wheelbase, newly classified.
GT3 GT3 2.0L 4V engines now unrestricted. #32190enginefasterengineGT3 2.0L 4V engines may run unrestricted at 2195 lbs minimum weight.
GT3 TB correction to wing wording #32191wordingwordingGT3 wing wording corrected; single element airfoil maximum chord length stays 10.75 inches.
GT3 Request to add Fiat to GT3 CARS #31803cars addedaddedGT3 adds Fiat Spider 2000, years 79-81, RWD, 89.76" wheelbase.
GT3 Request to add Fiat to GT3 CARS #31804cars addedaddedGT3 adds Fiat X-19, years 72-89.
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.
GT3 31032 correction to weight #31525weight -210 lbsfasterweightGT3 Fun Cup Beetle Sealed minimum weight drops 210 lbs, to 1850.
GT3 Add TCR cars to GT3 #31540cars addedaddedGT3 adds TCR cars: Audi RS3 LMS, Honda Civic Type R, Hyundai i30N, Volkswagen Golf GTI at 3100–3200 lbs with 200 tread wear tires.
GT3 Please approve 1964-1968 Ford Cortina GT for competition in GT# #30941cars addedaddedGT3 Ford Cortina GT 1964-1968 added to classified cars list.
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.
GT3 Request car classification #31032cars addedaddedGT3 Volkswagen Fun Cup Beetle EVO3 classified, sealed SOHC 1984cc engine, 2060 lbs minimum weight.
1:44.758Troy Ermish · fastest of 14 · top 5 within 4.6s+0.179s (+0.17%)
1:46.694Troy Ermish · fastest of 13 · top 5 within 4.1s+0.364s (+0.34%)
145.8Stacy Wilson
1:50.427Drew 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
+3.912squal +5.669s
103.7%qual 105.4%
20 rule changes (GT3: 6, AS: 14)7 cars added · 3 induction · 3 weight · 2 engine · 4 wording · 1 other · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two locations and 6010 to 6014X in TA2 Appendix. · GT3 permits current FP spec line cars to compete while maintaining full FP rule set. · 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. · GT3 Mazda MZR 2.0L fuel induction restrictor increases from 31 to 32 mm. · GT3 Mazda Renesis and 13B Bridgeport choke size corrected to 42mm. · 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. · GT3 Mazda MZR and MZR/L5-VE fuel induction size increases from 31 to 32. · GT3 Honda Prelude 1992-1997 2dr FWD 104" wheelbase newly classified.showhide
GT3 Request to Update GTA Obsolete Part Numbers #30615wordingwordingGTA part numbers updated: 0-80541-1 to 0-80541-2 in two locations and 6010 to 6014X in TA2 Appendix.
GT3 Request to Permit FP cars in GT3 #30611cars addedaddedGT3 permits current FP spec line cars to compete while maintaining full FP rule set.
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.
GT3 Mazda MZR 2.0L Engine #30455inductionfasterinductionGT3 Mazda MZR 2.0L fuel induction restrictor increases from 31 to 32 mm.
GT3 Disfranchised GT3 Mazda, correct choke size #30570inductioninductionGT3 Mazda Renesis and 13B Bridgeport choke size corrected to 42mm.
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.
GT3 Mazda MZR SIR Sizing #29555inductionfasterinductionGT3 Mazda MZR and MZR/L5-VE fuel induction size increases from 31 to 32.
2:21.882Michael Lewis · fastest of 12 · top 5 within 3.0s
2:24.231Tony Ave · fastest of 12 · top 5 within 3.0s
149.5Jeff Dernehl
2:27.045Gregory Eaton · fastest of 18 · top 5 within 0.6s
2:27.668Gregory Eaton · fastest of 15 · top 5 within 1.5s
149.2Gregory Eaton
+3.437squal +5.163s
102.4%qual 103.6%
33 rule changes (GT3: 17, AS: 16)8 cars added · 4 engine · 4 induction · 2 weight · 1 aero · 1 suspension & brakes · 10 wording · 3 other · GT1/GT2/GT3/GTL/GTX turbocharging and supercharging now permitted if listed on spec line. · 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. · 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 · GT3 Mazda 12A Peripheral Port added, 2300 cc, 2300 lbs, SIR head, 2 valves per cylinder. · TA2 Gurney flap wording clarified: replace 'wicker bill' and 'wicker' with 'Gurney flap' throughout wing specifications. · STO rear wing rules clarify that wicker is called Gurney flap in two places; no performance change. · GT Gurney flap wording clarified: wickerbill and tab terminology replaced with Gurney flap throughout sections 9.1.2.F.7.b. · GT3 4v SIR fuel induction increases from 31 to 32 mm across 20 engine variants. · GT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. · GT3 Nissan KA24E loses 32mm choke option at 2280 lbs for 2011-2012. · GT3 Mazda MZR L5-VE fuel induction changed to 31mm SIR, weight increased to 2195 lbs, direct injection prohibited. · 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. · GT1, GT2, GT3, GTL, GTX may use bonded-glass factory windshields without clips or straps if attached per original specifications. · GTX Misc. adds Factory Five Type 65 Coupe R Ford 302/351 and 5.0/5.2L NA at 2600 lbs, plus Ferrari 458/488 Challenge, Ford FP350S, Chevrolet C6, Lamborghini Super Trofeo. · GT3 Mazda 13B Bridgeport restrictor reduced from 44mm to 42mm. · GT3 Alfa 4C turbocharged 1742cc classified with 33mm restrictor, minimum weight 2325 lbs. · GT3 Mazda MZR/L5-VE gets unrestricted fuel induction, drops to 1950 lbs minimum weight, limited to GT2 prep. · GT3 adds Honda K20C1 turbocharged engine, 1928 cc, 33 mm restrictor, 2350 lbs minimum. · GT3 wing end plates change from 11.00 × 4.00 inch rectangle to maximum 64 square inches. · GT3 Nissan adds SR16VE engine, 1596 cc DOHC, 1690 lbs, unrestricted fuel induction.showhide
GT3 GT Category Wording #29193wordingaddedGT1/GT2/GT3/GTL/GTX turbocharging and supercharging now permitted if listed on spec line.
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.
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
GT3 Request to add Mazda 12A Peripheral Port to GT3 rule set #28842cars addedaddedGT3 Mazda 12A Peripheral Port added, 2300 cc, 2300 lbs, SIR head, 2 valves per cylinder.
GT3 TA2 Gurney flap wicker clarification #28874wordingwordingTA2 Gurney flap wording clarified: replace 'wicker bill' and 'wicker' with 'Gurney flap' throughout wing specifications.
GT3 STO Gurney flap wicker clarification #28883wordingwordingSTO rear wing rules clarify that wicker is called Gurney flap in two places; no performance change.
GT3 GT Gurney flap wicker clarification #28909wordingwordingGT Gurney flap wording clarified: wickerbill and tab terminology replaced with Gurney flap throughout sections 9.1.2.F.7.b.
GT3 GT3 4v SIR size increase. #28931inductionfasterinductionGT3 4v SIR fuel induction increases from 31 to 32 mm across 20 engine variants.
GT3 Request for Addition to GT3 Approved Turbo List #27576cars addedaddedGT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists.
GT3 Request Nissan KA24E specifications #28808inductionremovedinductionGT3 Nissan KA24E loses 32mm choke option at 2280 lbs for 2011-2012.
AS weight adjustments for 2020 season #28785weight -50 lbs
GT3 Error Regarding Mazda Engine Listing #28119induction +245 lbsslowerinductionGT3 Mazda MZR L5-VE fuel induction changed to 31mm SIR, weight increased to 2195 lbs, direct injection prohibited.
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.
GT3 Windshield Clips #27323otheraddedGT1, GT2, GT3, GTL, GTX may use bonded-glass factory windshields without clips or straps if attached per original specifications.
GT3 Request Factory Five Daytona coupe classification #26308cars addedaddedGTX Misc. adds Factory Five Type 65 Coupe R Ford 302/351 and 5.0/5.2L NA at 2600 lbs, plus Ferrari 458/488 Challenge, Ford FP350S, Chevrolet C6, Lamborghini Super Trofeo.
GT3 Request restrictor size change request #26958inductionslowerinductionGT3 Mazda 13B Bridgeport restrictor reduced from 44mm to 42mm.
1:58.194Michael Lewis · fastest of 17 · top 5 within 2.2s
1:59.045Tony Ave · fastest of 16 · top 5 within 1.7s
149.6Jeff Dernehl
1:54.469Pete Frost · only car
1:57.688Pete Frost · only car
145.9Pete Frost
-1.357squal -3.725s
98.9%qual 96.8%
1:55.124Bryce Cornet · fastest of 8 · top 5 within 2.3s
2:15.816Bryce Cornet · fastest of 8 · top 5 within 4.9s
135.7Bryce Cornet
+16.771squal -3.070s
114.1%qual 97.4%
2:02.938Gregory Eaton · fastest of 17 · top 5 within 0.8s
2:03.900James Jost · fastest of 16 · top 5 within 2.1s
153.9James Jost
+4.855squal +4.744s
104.1%qual 104.0%
12 rule changes (GT3: 8, AS: 4)4 cars added · 2 weight · 1 engine · 1 induction · 2 wording · 2 other · AS Spec Mustang (SMG) added as Restricted Prep class. · GT3 Mazda 12A Bridgeport gains optional 42mm choke at 2010 lbs minimum weight. · 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. · GTX tube frame cars now allowed fuel injection with maximum 90mm throttle body. · GTX adds Ligier JS2 R classification with restrictor and minimum weight. · GT3 Mazda 13B and Renesis engines completely respecified with new induction types and weights ranging 2080–2350 lbs. · GT1 and GT2/3/Lite remove ride height ground clearance rules; cars may now touch ground when tires deflate. · GT3 13B Street Port removed; 13B Peripheral Port weight raised to 2400 lbs; 13B Bridge Port weight raised to 2400 lbs; Renesis Street Port removed; Renesis Peripheral Port weight raised to 2450 lbs; Renesis Bridge Port weight raised to 245… · GT3 adds Mitsubishi 4G69 SOHC engine, 2378 cc, 2195 lbs, 31mm SIR. · AS adds Spec Mustang SMG classification with 107.1 wheelbase, 3.73 gears, 355mm front and 300mm rear brakes. · GTX FIA GT3: Audi R8 now 40 mm restrictor and 2900 lbs; BMW Z4 now 70 mm restrictor and 2800 lbs; Ferrari 488 now 35 mm restrictor, TIR, and 3025 lbs.showhide
AS Request to add SMG to 9.1.6.B.1 AS Intent #27140cars addedaddedAS Spec Mustang (SMG) added as Restricted Prep class.
GT3 Requesting Increase in Choke Diameter for Mazda 12A Bridgeport #27043inductionaddedinductionGT3 Mazda 12A Bridgeport gains optional 42mm choke at 2010 lbs minimum weight.
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.
GT3 Request GTX Fuel injection for previous GT-1 tube frame cars #26141engineaddedengineGTX tube frame cars now allowed fuel injection with maximum 90mm throttle body.
GT3 Request to Classify Ligier JS2 R #26535cars addedaddedGTX adds Ligier JS2 R classification with restrictor and minimum weight.
GT3 26076 revised Spec line chart #26528otherunclearGT3 Mazda 13B and Renesis engines completely respecified with new induction types and weights ranging 2080–2350 lbs.
GT3 Request Ride Height Clarification #26600wordingfasterGT1 and GT2/3/Lite remove ride height ground clearance rules; cars may now touch ground when tires deflate.
GT3 Request clarification on bridge porting for rotary #26076weightslowerweightGT3 13B Street Port removed; 13B Peripheral Port weight raised to 2400 lbs; 13B Bridge Port weight raised to 2400 lbs; Renesis Street Port removed; Renesis Peripheral Port weight raised to 2450 lbs; Renesis Bridge Port weight raised to 245…
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.
GT3 GTX Homologation table update #26034otherunclearGTX FIA GT3: Audi R8 now 40 mm restrictor and 2900 lbs; BMW Z4 now 70 mm restrictor and 2800 lbs; Ferrari 488 now 35 mm restrictor, TIR, and 3025 lbs.
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 GT3'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.