SM vs GT1 vs AS vs P2 pace at Buttonwillow Raceway Park
Quickest here:SM 2:00.831 William Wallis, Cal Club 2025 qualifying · GT1 1:39.857 Michael McAleenan, Cal Club 2026 qualifying · AS 1:55.849 Roger Eagleton, Cal Club 2025 race · P2 1:37.278 Tim Day Jr, Cal Club 2026 qualifying
SMGT1ASP2solid race · dashed qualifying · slower is lower
SMGT1ASP2solid race · dashed qualifying · each class's best lap as a share of SM's at the same event (the reference class, changeable above); 100% is level, higher is quicker
Event
SM
GT1
AS
P2
Qual best
Race best
Trap
Qual best
Race best
Trap
vs SM
% of SM
Qual best
Race best
Trap
vs SM
% of SM
Qual best
Race best
Trap
vs SM
% of SM
Cal Club 2026 CALCL262026-02-21
2:01.392Ryan Busk · fastest of 18 · top 5 within 0.8s+0.561s (+0.46%)
2:02.486William Rasmussen · fastest of 18 · top 5 within 1.3s+0.836s (+0.69%)
127.3Sam Rezai+23.4 mph (+22.6%)
1:39.857Michael McAleenan · fastest of 2-4.110s (-3.95%)
1:41.045Michael McAleenan · fastest of 2-1.260s (-1.23%)
167.6Michael McAleenan+53.8 mph (+47.3%)
-21.441squal -21.535s
82.5%qual 82.3%
1:56.812Ross Murray · fastest of 2+0.367s (+0.32%)
1:56.314Ross Murray · fastest of 2+0.465s (+0.40%)
135.2Ross Murray+26.5 mph (+24.4%)
-6.172squal -4.580s
95.0%qual 96.2%
1:37.278Tim Day Jr · only car
1:39.758Tim Day Jr · only car
155.4Tim Day Jr
-22.728squal -24.114s
81.4%qual 80.1%
19 rule changes (SM: 3, GT1: 5, AS: 11)5 cars added · 3 weight · 2 induction · 9 wording · AS Chevy LS adds Edelbrock Performer RPM 71187 intake manifold with MSD 6014 ignition and 4776 Holly carburetor as spec line option. · GT1 adds Porsche 992.1 GT3 Cup (2022-2025) with OEM ABS, traction control, RSR bumper, canards, and any exhaust allowed. · AS Ford Mustang Restricted Prep engines lose 3 mm restrictor plate, from 64 mm to 61 mm. · GT1-ST Acura NSX GT3 EVO 22 weight drops 100 lbs to 3000 lbs. · 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 weight reduced 50 lbs to 3400. · Acura NSX GT3 EVO 22 reclassified from GT1 to GT1-ST with 3100 lbs minimum weight. · GT1 LS Limited Prep Engine expands to include LS1, LS2, LS3, LS6 with 11:1 max compression. · AS Ford Mustang GT 5.0 2018- weight reduced from 3600 to 3525 lbs. · AS Ford Mustang GT 05-14 Restricted Prep Engine gains alternative gear ratios: 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 fine; level 2 and 4 may carry $500 fine. · AS Ford Mustang GT 5.0L (15-17) flat plate restrictor reduced from 67mm to 64mm. · AS LS1/LS6 5.3L truck engine gains four approved intake part numbers: 12561269, 88894095, 89017363, 89017364. · SM cars limited to one set of Hoosier SM 7.5 P205/50/ZR17 per Super Tour event weekend for dry sessions. · AS Flotek Head plunge cut dimensions figure updated in GCR Section 9.1.6. · AS class notes cleanup: multiple Camaro, Firebird, CTS-V, Challenger, Mustang specs and fuel cell/ECM/head restrictions removed. · AS Spec Lines removes ECM flexibility restriction from five Cadillac and Chevrolet/Pontiac V8 models. · Acura NSX GT3 EVO 22 classified in GT1 with 3500cc twin turbo V-6, 3100 lbs, max RPM 7500.showhide
AS Edelbrock manifold (& timing kit) to Chevy LS Spec Lines Request #39055cars addedneutralAS Chevy LS adds Edelbrock Performer RPM 71187 intake manifold with MSD 6014 ignition and 4776 Holly carburetor as spec line option.
GT1 Request for Addition of Porsche 992.1 GT3 Cup into GT1 #39322cars addedneutralGT1 adds Porsche 992.1 GT3 Cup (2022-2025) with OEM ABS, traction control, RSR bumper, canards, and any exhaust allowed.
AS Restrictor Plate Change for Gen 2 Ford Coyote Engine #39501inductionslowerAS Ford Mustang Restricted Prep engines lose 3 mm restrictor plate, from 64 mm to 61 mm.
GT1 NSX Parity With Other GT3s Let Alone a GT1 Car #39311weight -100 lbsfasterGT1-ST Acura NSX GT3 EVO 22 weight drops 100 lbs to 3000 lbs.
AS 1994 Mustang Spec Line Request #39104wordingunclearAS 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 lbsfasterAS Cadillac CTS-V 04-07 Restricted Prep weight reduced 50 lbs to 3400.
GT1 RM 25-06 GT1 reclassify the Acura NSX GT3 EVO 22 to GT1-ST #39101cars addedneutralAcura NSX GT3 EVO 22 reclassified from GT1 to GT1-ST with 3100 lbs minimum weight.
GT1 Correction to Limited prep LS Chevy engine for GT1 #38902cars addedneutralGT1 LS Limited Prep Engine expands to include LS1, LS2, LS3, LS6 with 11:1 max compression.
AS RE: Previous Letter 37695 Update #38245weight -75 lbsfasterAS Ford Mustang GT 5.0 2018- weight reduced from 3600 to 3525 lbs.
AS Errors and Omissions #38234wordingneutralAS Ford Mustang GT 05-14 Restricted Prep Engine gains alternative gear ratios: 3.66, 2.43, 1.69, 1.32, 1.00, .65
SM SMX Data Submission - Penalties #38248wordingneutralSMX drivers must submit data acquisition files on time or face suspension and $250 fine.
SM Committee) SMX Penaly Clarification updated language #38337wordingneutralSMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fine; level 2 and 4 may carry $500 fine.
AS Errors and Omission #38055inductionslowerAS Ford Mustang GT 5.0L (15-17) flat plate restrictor reduced from 67mm to 64mm.
AS Request to Add LS1/LS6 Intakes for 5.3L Truck Engine EnO #38197wordingneutralAS LS1/LS6 5.3L truck engine gains four approved intake part numbers: 12561269, 88894095, 89017363, 89017364.
SM Clarify Tire Marking Regs #38005wordingneutralSM cars limited to one set of Hoosier SM 7.5 P205/50/ZR17 per Super Tour event weekend for dry sessions.
AS Flotek Head Plunge Cut Inconsistencies #37502wordingunclearAS Flotek Head plunge cut dimensions figure updated in GCR Section 9.1.6.
AS Notes clean up #37693wordingneutralAS class notes cleanup: multiple Camaro, Firebird, CTS-V, Challenger, Mustang specs and fuel cell/ECM/head restrictions removed.
AS Race memo #37902wordingunclearAS Spec Lines removes ECM flexibility restriction from five Cadillac and Chevrolet/Pontiac V8 models.
GT1 Request to Classify Acura NSX GT3 Evo 22 #37367cars addedneutralAcura NSX GT3 EVO 22 classified in GT1 with 3500cc twin turbo V-6, 3100 lbs, max RPM 7500.
Cal Club 2025 CALCL252025-02-22
2:00.831William Wallis · fastest of 16 · top 5 within 0.9s
2:01.650Nick Leverone · fastest of 16 · top 5 within 0.3s
103.9Evan Jacobs
1:43.967Michael Lewis · only car
1:42.305Michael Lewis · only car
113.8Michael Lewis
-19.345squal -16.864s
84.1%qual 86.0%
1:56.445Roger Eagleton · fastest of 3 · top 3 within 4.0s
1:55.849Roger Eagleton · fastest of 4 · top 4 within 5.3s
108.7Roger Eagleton
-5.801squal -4.386s
95.2%qual 96.4%
168 earlier rule changes on record, in force before Cal Club 2025 (from 2019)30 cars added · 20 weight · 16 engine · 12 induction · 7 tyres & wheels · 5 aero · 5 suspension & brakes · 70 wording · 3 other · AS Ford Mustang Coyote engines increase restrictor to 80mm from 64mm or 67mm. · AS Mustang GT 05-14 4.6L loses 300 lbs; 15-17 and 2018+ models lose 61mm and 60mm restrictors respectively. · AS class gear ratio options specified for multiple American muscle cars, including Cadillac CTS-V, Chevrolet Camaro, Ford Mustang, Dodge Challenger, and Pontiac GTO. · AS LS-engine cars gain ECU freedom; Camaro/Firebird 93-02 LS1 removes fuel cell location restriction. · GT1 LS1 Limited Prep engine added, 2600 lbs with driver, 383 cubic inches max, hydraulic roller cam, 750 cfm carb. · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement. · GT1-ST restrictor sizes removed for 13 cars; new specs not printed in letter. · GT1-ST Lamborghini Huracan GT3 Evo and 2019+ GT3 both shift to Unrestricted from 39mm and 52mm restrictors. · P2 2000cc Pinto engine car minimum weight set to 1335 lbs. · SMX allows OE instrument cluster relocation for aftermarket dash mounting, with wiring re-routed only; alternate gauges now permitted. · GT1 Mazda 26B engine classified at 2850 lbs minimum weight. · AS Ford Mustang GT models gain alternate transmission ratio options for 2024-09-01. · SMX Spec MX-5 camera requirement wording changed; non-functioning recorder now grounds for penalty or disqualification. · SMX Spec MX-5 must run latest AIM Data Logger Spec MX-5 ECU Protocol; wording clarification for technical compliance. · SMX Mazda Miata OE versus OEM definitions clarified in GCR Section 9.1.7.1. · SM and SMX shifter bushing rules clarified: alternate bushing at shift lever bottom now allowed. · AS Ford Mustang GT 5.0L (2018-) classified at 3600 lbs with 60mm restrictor, Brembo BBK permitted. · AS Chevrolet Camaro 1LE (2016-) classified with 3600 lbs minimum weight, 60mm restrictor, 275 tires. · AS Chevrolet/Pontiac Camaro & Firebird 82-92 5.7L LS1 classified at 3200 lbs with 65mm restrictor plate required. · AS Chevrolet Camaro, Firebird, and Ford Mustang models permitted to use Flo Tek cylinder heads. · GT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR. · GT1 Camaro 1993-2002 classification updated; 2010- model separately classified. · P2 Spec ECU engine modifications clarified: oil system, ECU, and exhaust unrestricted only. · P2 FIA Group CN spec notes clarified: Series changed to Challenge, documentation requirement moved to online link. · AS Camaro/Firebird and GTO LS1 connecting rods approved: Callies CSC6100DS6A2AH, Scat 2-1CR6100-944, GM 12649190. · AS Cadillac CTS-V, Chevrolet Camaro SS, Dodge Challenger, Ford Mustang GT, Pontiac GTO allowed 11" wheels until 3/1/25. · Chevrolet Camaro, Pontiac Firebird 70-81 Full Prep classified AS at 3400-3600 lbs with 250 lb weight reduction. · AS class: multiple cars gain fuel cell placement note allowing 24 inches from standard tank, unrestricted filler location. · Chevrolet Camaro 16- Full Prep classified into AS at 3400 lbs with 250 lb weight reduction. · AS adds Ford Mustang GT 05-14 Restricted prep Engine with 62mm FPR, 3400 lbs minimum, 18-inch wheels. · GT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed. · GT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors. · GT2/3 Nissan, Mazda, Mitsubishi 4G93, QR25DE/DD, QE25DE/DD Direct Injection now permitted per 9.1.2.F.7.5.E. · Lamborghini Huracan GT3 EVO(1) and GT3 added to GT1-ST at 3000 and 3100 lbs minimum weight respectively. · GT1 Trick Flow Specialties Ultra 18 Degree GM Cylinder Head Part #TFS-3181T001-CO1 allowed. · P2 AMAC modified engine range clarified to 2008 and older stock engines only, restrictor 38mm, weight 1025 lbs. · P2 Suzuki GSX-R1000 07/08 engine crankcase may swap to GSX-S1000 16/19 part #11301-04840. · GTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL. · P2 Table 1 corrects engine date ranges and brand specifications for Stock and Modified engines across multiple car models. · AS crate motor part number specified: GM Performance CT400 P/N 19370604 engine assembly for GM vehicles. · AS Spec Lines Ford Mustang GT 5.0L (15-17) max wheel size increases to 19.0 inches. · AS Dodge Challenger 5.7L/6.1L/6.4L V8 now permits SPC-66045 alternate front upper control arms. · AS Dodge Challenger 5.7L/6.1L/6.4L V8 allows alternate front brake caliper adapters for updated or backdated components. · Fields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight. · P2 side body height requirement clarified: outermost surface between wheel openings must equal front axle centerline height. · P2 closed cockpit single seat cars now prohibited unless specifically allowed in Table 1. · GT1 Mercedes AMG GT3 16-19 preparation wording changed to per FIA GT3 homologation. · P2 engine table wording updated; redundant effective date language removed. · P2 motorcycle engines: 2011+ Kawasaki restrictor reduced to 34mm, minimum weight raised to 1100 lbs; 2009+ other brands weight raised to 1100 lbs. · GT1 sequential transmission weight penalty reduced from 50 to 25 lbs. · GT1-ST Porsche 992 GT3 Cup classified with 3997cc displacement, 2950 lbs minimum weight. · Sebeco NP01-EVO and Elan NP01 Mazda 2.0L MZR added to P2, 1600 lb minimum, no restrictor required. · P2 Radical SR3/SR4/Cup/Club Sport/Pro-Sport/PR6 removes assisted shifting requirement across all spec lines. · P2 chassis rules clarified to allow composite materials in non-fully-composite construction; anti-intrusion panel attachment standardized; Stohr and converted F600 cars added with specific allowances. · Unable to summarize: the change to P2 Engine Table Spec Line B.1 is not detailed in the provided text. · SM Mazda MX-5 Miata 01-05 weight increases to 2450 lbs, or 2465 with alternate bore. · GT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870. · GT1 Trans Am bodywork weight penalty reduced from 100 lbs to 75 lbs. · GT1 Chevrolet RO7, Ford FR9, and Dodge R7 weight penalties reduced from 50 to 25 lbs. · AS allows Hoosier W2 tyre option in addition to R7, R6, WET/H20. · AS Dodge Challenger 08-20 adds two transmission ratio options: 2.97, 2.10, 1.45, 1.00, 0.74, 0.50 or 2.26, 1.58, 1.19, 1.00, 0.77, 0.63. · GT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only. · GT1 TransAm bodywork allowed with 100 lb. weight penalty. · AS Cadillac CTS-V 6.0L V8 removes 50 lbs weight penalty for 295 tire size. · P2 chassis construction rules clarified: fully composite or partially composite requiring composite for mobility allowed; partial composite must roll without composite parts. · P2 classification wording cleaned up in GCR section 9.1.8.C and Contents. · P2 Oldsmobile cam rules clarify aftermarket manufacturer requirements; wording only. · SM Majors must run authorized Penske shock and mount; Regional competitors' requirement eligibility clarified. · Mercedes Benz AMG GT3 classified in GT1 at 3050 lbs with 40mm restrictors, prepared per FIA GT3 homologation. · GT1 wheels: 18-inch tyres get wider rear allowance, from 13 to 14 MAX inches. · P2 adds Beasley B2 spec line with 1350 lbs, Mazda 12A, 40.5mm venturi, 16.5in wing. · P2 wing specs correct terminology from 'cord' to 'chord' for 16.5in single or dual element wings. · P2 Converted F5 cars reclassified as Converted F500 cars; suspension must comply with F500 requirements, minimum width 55 inches. · GT1 allows 17-inch wheels newly; 18-inch wheels require 50 lb penalty; maximum widths 12 front/13 rear, or 13/14 for 18-inch. · P2 motorcycle engines increase to 1505cc max, two-stroke to 1205cc max; automotive engines gain 50 lbs minimum weight to 1350. · SMG long tube headers: Borla PN 17237 discontinued, Kooks PN 11312000 and American Racing PN MT3-05134300LSNC approved alternatives. · AS Mercury Capri (79-86) removed as individual spec line, merged into Ford Mustang (79-93) spec line. · AS Spec Mustang SMG loses 3.73 gear ratio and 355/300 mm brake specification. · AS Chevrolet, Pontiac, Ford full prep engines now permit alternate cylinder heads with restrictor plate ALL26180 and 1.250 inserts ALL26186 for regional competition. · P2 Control Area definition narrowed; aerodynamic attachments and vertical structures like turning vanes now prohibited. · P2 Engine Table Spec Line B.1 changed effective 1-1-22, details not provided in excerpt. · P2 Control Area definition clarified: floor extensions and aerodynamic attachments on bottom or top side now explicitly included. · AS Chevrolet/Pontiac Camaro & Firebird 93-02 now allow BMR AA004 or UMI 2310 adjustable front upper control arms. · AS Pontiac GTO 04-06 LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tire. · GT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight. · P2 CN Honda K20A-FD2 engine rebuild rules clarified: machining prohibition replaced with specific restrictions on balancing, porting, polishing, valve jobs, cylinder honing. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix. · Converted F5 cars in P2 minimum width reduced to 55 inches from F5 spec. · P2 clarifies minimum body width requirement between front and rear wheels for Ralt RT40, RT41, Swift 008, 014. · AS Cadillac CTS-V 6.0L V8 removes 50 lbs tire size penalty, making it lighter. · AS consolidates seven SN95 Mustang spec lines into three: 94-04 including Cobra, 94-95 5.0/5.8, and 96-04 4.6L two/four valve. · AS Camaro/Firebird LT1/LS1 transmission code changes to 6362; Mustang GT 4.6L/5spd changes to 5.0L/6spd with 300 lbs weight reduction. · AS Camaro/Firebird and Mustang GT gear ratio specifications restored with alternate sets permitted. · AS Chevrolet Camaro & Firebird, Ford Mustang variants, Mercury Capri minimum weights increase 50 lbs across all model years. · P2 tonneau covers now allowed to meet minimum dimensions; equipment attachment requirements clarified. · P2 multiple chassis models remove effective dates from Table 1 specifications. · P2 engines limited to 4 valves per cylinder maximum across all three spec lines. · SM adds procedures for testing obsolete part replacements and BOP updates in sanctioned events with CRB approval. · AS Mustang 4.6L/5spd loses 300 lbs; 5.0L/6spd gains 56mm restrictor requirement. · AS CTS-V LS6 and LS2 may now use Driveshaft Shop carbon fiber driveshaft for durability. · AS Chevrolet Camaro SS V8 6.2L model years extended from 10-13 to 10-15. · P2 adds new spec line for 2-cycle 3-cylinder engine up to 820cc with 10 front and 14-15 rear wheel width. · Ford Mustang GT 5.0L 15-17 Restricted Preparation classified in AS with 55mm flat plate restrictor required. · 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 10-13 275 tire removed; Challenger 08-20 gains 315 tire option at 3600 lbs. · AS Camaro & Firebird (93-02) and Mustang GT (05-14) specifications restored with 200 lb weight reduction for permitted heads. · AS Dodge Challenger 08-20 gains 6.1L and 6.4L V8 options; 5.7L weight rises to 3500 lbs on 295 tyres, 3600 on 315 tyres. · AS Camaro/Firebird (93-02) and Mustang Coupe GT (05-14) consolidated into single specs with 100 lb and 300 lb weight reductions respectively. · P2 Honda K20A-FD2 intake restrictor reduced from 55mm to 50mm, making cars faster. · SM aftermarket radiators must mount in original location, maintain core plane, require no body modifications, block openings, keep one OEM fan in stock location; 1990-1997 cars may install upper radiator seal NA75-50-OK7A. · GT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line. · P2 rear wing requirements clarified: standard wing 6×12 inches, end plates 14-inch square; alternate 110cm width wing 9×18 inches, end plates 14×18 inches. · AS Dodge Challenger 5.7L V8 gets iron block requirement, 10.5:1 compression max, intake valve 12.7 mm, exhaust 12.3 mm, intake duration 188°, exhaust duration 205°. · AS Dodge Challenger 08-14 rear spoiler part number changes from 1GL20RXF to 1GL20TZZAB. · GT1 adds Trans Am spec engines: Chevrolet R07, Ford FR9, Dodge R7, each with 50 lbs. weight penalty. · SM rear brake calipers may use single bracket under upper retaining bolt to prevent pin failure. · AS class pursues specified list of eligible tires; details of tire changes not provided in letter. · AS class pursuing specified list of eligible tires; details pending further communication. · No restrictor plate change implemented; 2021 AS Mustang Coyote under evaluation. · AS 2005-2009 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 reclassified to AS; full preparation classification approved effective 2020-07-01. · AS class cylinder head replacement options under review; implementation planned for 2021 season. · AS Mustang, Camaro, Firebird, Capri max brake rotor diameter increases from 12.2 to 13.1 inches. · AS rotor diameter increase approved; see Fastrack letter #28748 for details. · TA2 Gurney flap wording clarified: terminology standardized to 'Gurney flap', height limits and thickness specifications remain 0.50 inch / 0.625 inch or 0.375 inch / 0.0625 inch depending on configuration. · STO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules. · GT1 Gurney flap wicker clarification: terminology standardized from lips/tabs/wicker to flaps throughout specifications. · GT classes clarify Gurney flap wording, replacing wickerbill/tab terminology with flap; specifications unchanged. · Elan NP01 classified in P2 Table 1 as Spec Line car with 2000cc displacement and P2 Engine Table restrictor. · AS Chevrolet/Pontiac Camaro & Firebird (82-92) loses 50 lbs, to 3500. · P2 Enterprises Sports Racer adds 55mm flat plate intake restrictor Part # WM303013 as alternative to SIR. · P2 Enterprise Sports Racer 2.3L engine now requires SIR or Flat Plate restrictor sized in 0.5mm increments. · P2 fly-by-wire throttle control wording clarified: stock ECUs with drive-by-wire must activate original throttle shaft mechanism. · 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 200 lb weight reduction, up from 150 lb. · 05-10 Ford Mustang Coupe GT 4.6L OHC classified AS with 3200 lbs minimum weight, HR cam restricted prep. · AS 10-15 Chevrolet Camaro Full Prep classified with 3400 lbs base weight, over 313 CID engine 3700 lbs maximum. · GT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications. · GT2/ST Ford 5.0L Coyote 3rd Gen OEM added at 3200 lbs with Boss intake manifold permitted. · Factory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs. · GT1 sequential shifting transmission weight penalty reduced from 75 to 50 lbs. · GT1 non-18-inch-wheel cars now get 18-inch wheels with 50 lb penalty, down from 100 lb. · GT1 Spec Lines allows 5 Star NASCAR Camaro 2018+ body for General Motors Corporation. · P2 adds BMW to motorcycle-based engine options in 4-cycle line alongside Kawasaki, Suzuki, Yamaha, Honda. · AS Spec Mustang (SMG) added as Restricted Prep class. · P2 Honda K20A-FD2 non-composite chassis must use 55mm flat plate intake restrictor at 1500 lbs minimum weight. · GT1 Porsche 944/968 classified: 2981cc twin turbo, 2585 lbs minimum weight. · P2 motorcycle engines: Stock restrictor 36.5mm to 35mm, modified 37.5mm to 34mm; B.5 restrictor 37.5mm to 33mm. All weights increase 25 lbs. · AS class minimum ride height clarified to 5 inches measured at rocker panel, excluding seams and cladding. · GT1 allows Trans Am rear wing, 12" chord, 72" span, 1/2" wicker, 100 sq in endplates, no weight penalty. · P2 cars limited to power application on maximum two wheels, effective 2019-07-01. · P2 Enterprise minimum weight increases to 1375 lbs; peak horsepower of sealed ESR engine reduced per CRB specification. · AS Ford Mustang (79-93) 313 CID and under loses 100 lbs to 3150; over 313 CID loses 100 lbs to 3450. · GTX tube frame cars gain fuel injection with 90mm maximum throttle body size. · Ligier JS2 R classified in GTX, no performance parameters specified in filing. · GT1 and GT2/GT3/LITE ride height requirements removed from GCR sections 9.1.2.D.5.a.1 and 9.1.2.F.7.b. · P2 stock engine restrictor shrinks to 35.0mm and weight rises to 1025 lbs; modified engine restrictor to 34.0mm, weight to 1125 lbs; line B.5 restrictor to 33.0mm, weight to 1185 lbs. · P2 Line A.1 restrictor reduced from 40mm to 38mm. · SM fuel pump and filter must be Mazda or OEM Equivalent part. · AS Spec Mustang (SMG) newly classified with 107.1 wheelbase, 3.73 gears, 355mm front brakes, 300mm rear. · SM 1999-2000 model year cars may use replacement Mazda ECU and injector harnesses, unmodified. · SM electrical rules reorganized and clarified; alternator external regulation now prohibited except via OEM ECU/kill switch. · SM removes tire tread protrusion beyond fender opening requirement from GCR 9.1.7.C.5. · GTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified. · P2 Spec Line cars now allow 1345cc Hayabusa stock engines at 1050 lbs with 30mm restrictor. · P2 Group CN Honda K20A-FD2 55mm restrictor implementation delayed from 1/1/2019 to 3/1/2019. · P2 Honda K20A-FD2 in CN chassis must use stock intake manifold with 64mm throttle body and 55mm restrictor at 1500 lbs minimum weight.showhide
AS Increase Coyote Engine Restrictor to 80mm #36177inductionfasterAS Ford Mustang Coyote engines increase restrictor to 80mm from 64mm or 67mm.
AS Performance Pack for 2015+ Mustang #36867enginefasterAS Mustang GT 05-14 4.6L loses 300 lbs; 15-17 and 2018+ models lose 61mm and 60mm restrictors respectively.
AS Gear Ratios #37131wordingneutralAS class gear ratio options specified for multiple American muscle cars, including Cadillac CTS-V, Chevrolet Camaro, Ford Mustang, Dodge Challenger, and Pontiac GTO.
AS ECU specs for LS engine #37208enginefasterAS LS-engine cars gain ECU freedom; Camaro/Firebird 93-02 LS1 removes fuel cell location restriction.
GT1 Addition of a limited prep LS Chevy engine for GT1 #37045cars addedneutralGT1 LS1 Limited Prep engine added, 2600 lbs with driver, 383 cubic inches max, hydraulic roller cam, 750 cfm carb.
GT1 Correct language regarding OEM Areo Devices #37137wordingneutralTA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement.
GT1 GT1-ST Adjustments #37481inductionunclearGT1-ST restrictor sizes removed for 13 cars; new specs not printed in letter.
GT1 Lamborghini Huracan GT3 Evo Restrictor Help #36254inductionfasterGT1-ST Lamborghini Huracan GT3 Evo and 2019+ GT3 both shift to Unrestricted from 39mm and 52mm restrictors.
P2 2000 cc Pinto Engine Car Weight #37187weightslowerP2 2000cc Pinto engine car minimum weight set to 1335 lbs.
SM E&O SMX Regs 9.1.7.1.D.5.u-.w #37070wordingneutralSMX allows OE instrument cluster relocation for aftermarket dash mounting, with wiring re-routed only; alternate gauges now permitted.
GT1 Request to Classify Mazda 26B Engine #36230cars addedneutralGT1 Mazda 26B engine classified at 2850 lbs minimum weight.
AS Mustang transmission ratios #36662wordingunclearAS Ford Mustang GT models gain alternate transmission ratio options for 2024-09-01.
SM SMX Camera Rule Correction #36496wordingneutralSMX Spec MX-5 camera requirement wording changed; non-functioning recorder now grounds for penalty or disqualification.
SM Committee) AIM ECU Protocol #36556wordingneutralSMX Spec MX-5 must run latest AIM Data Logger Spec MX-5 ECU Protocol; wording clarification for technical compliance.
SM Committee) OE versus OEM Definitons #36608wordingneutralSMX Mazda Miata OE versus OEM definitions clarified in GCR Section 9.1.7.1.
SM Committee) Shifter Bushing #36611wordingneutralSM and SMX shifter bushing rules clarified: alternate bushing at shift lever bottom now allowed.
AS Request for Classification of 2018-2023 mustang In #35764cars addedneutralAS Ford Mustang GT 5.0L (2018-) classified at 3600 lbs with 60mm restrictor, Brembo BBK permitted.
AS 6th gen Camaro limited prep #35733cars addedneutralAS Chevrolet Camaro 1LE (2016-) classified with 3600 lbs minimum weight, 60mm restrictor, 275 tires.
AS Chevrolet/Pontiac Camaro & Firebird (82-92) 5.7L V8 LS1 Alum BLK #35825cars addedneutralAS Chevrolet/Pontiac Camaro & Firebird 82-92 5.7L LS1 classified at 3200 lbs with 65mm restrictor plate required.
AS Full Prep Head #35891otherneutralAS Chevrolet Camaro, Firebird, and Ford Mustang models permitted to use Flo Tek cylinder heads.
GT1 Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslowerGT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR.
GT1 Camaro 1993- and 2010- #35652wordingneutralGT1 Camaro 1993-2002 classification updated; 2010- model separately classified.
P2 E&O - Correct FIA Group CN spec line notes #35900wordingneutralP2 FIA Group CN spec notes clarified: Series changed to Challenge, documentation requirement moved to online link.
AS Restricted Prep Aftermarket Parts Request #35682wordingneutralAS Camaro/Firebird and GTO LS1 connecting rods approved: Callies CSC6100DS6A2AH, Scat 2-1CR6100-944, GM 12649190.
AS Allowance of 11 #35824tyres & wheelsfasterAS Cadillac CTS-V, Chevrolet Camaro SS, Dodge Challenger, Ford Mustang GT, Pontiac GTO allowed 11" wheels until 3/1/25.
AS Request to Classify 1970-1981 Camaro and Firebird in AS #33659cars addedneutralChevrolet Camaro, Pontiac Firebird 70-81 Full Prep classified AS at 3400-3600 lbs with 250 lb weight reduction.
AS Fuel Cell 12 #34194wordingneutralAS class: multiple cars gain fuel cell placement note allowing 24 inches from standard tank, unrestricted filler location.
AS Please Classify the 6th Gen Into AS. #35448cars addedneutralChevrolet Camaro 16- Full Prep classified into AS at 3400 lbs with 250 lb weight reduction.
AS spec lines #35713cars addedneutralAS adds Ford Mustang GT 05-14 Restricted prep Engine with 62mm FPR, 3400 lbs minimum, 18-inch wheels.
GT1 Rear Blade Spoiler Clarification #35261aerofasterGT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed.
GT1 GT Direct Injection allowance and rules #35437enginefasterGT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors.
GT1 GT2/3 remove Direction Injection not allowed in Spec line notes #35439inductionfasterGT2/3 Nissan, Mazda, Mitsubishi 4G93, QR25DE/DD, QE25DE/DD Direct Injection now permitted per 9.1.2.F.7.5.E.
GT1 Request for Acceptance of Lamborghini Huracan GT3 in GT1-ST #34929cars addedneutralLamborghini Huracan GT3 EVO(1) and GT3 added to GT1-ST at 3000 and 3100 lbs minimum weight respectively.
GT1 Cylinder heads #35040wordingneutralGT1 Trick Flow Specialties Ultra 18 Degree GM Cylinder Head Part #TFS-3181T001-CO1 allowed.
P2 E&O - Clarify B.1 modified engine range in AMAC spec lines #35225wordingneutralP2 AMAC modified engine range clarified to 2008 and older stock engines only, restrictor 38mm, weight 1025 lbs.
P2 Replacement Engine Crankcase for 07/08 Suzuki GSX-R1000 Engines #35340engineunclearP2 Suzuki GSX-R1000 07/08 engine crankcase may swap to GSX-S1000 16/19 part #11301-04840.
GT1 Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules #34453wordingneutralGTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL.
P2 Correct Table 1 for Engine Date Range Specifications #35182wordingneutralP2 Table 1 corrects engine date ranges and brand specifications for Stock and Modified engines across multiple car models.
AS Crate Motor Part Numbers #32944wordingneutralAS crate motor part number specified: GM Performance CT400 P/N 19370604 engine assembly for GM vehicles.
AS Request wheel size change #33007tyres & wheelsfasterAS Spec Lines Ford Mustang GT 5.0L (15-17) max wheel size increases to 19.0 inches.
AS Alternative Upper Front Control Arms for Dodge Challenger #33352wordingneutralAS Dodge Challenger 5.7L/6.1L/6.4L V8 now permits SPC-66045 alternate front upper control arms.
AS Front Brake Caliper Adapters for Dodge Challenger #33353wordingneutralAS Dodge Challenger 5.7L/6.1L/6.4L V8 allows alternate front brake caliper adapters for updated or backdated components.
GT1 Please classify Fields Cardinal V8 #33784cars addedneutralFields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight.
P2 Clarify minimum side body height requirement #34143wordingneutralP2 side body height requirement clarified: outermost surface between wheel openings must equal front axle centerline height.
P2 Clarify closed cockpit single seat car allowance #34144wordingneutralP2 closed cockpit single seat cars now prohibited unless specifically allowed in Table 1.
GT1 Mercedes AMG GT3 Notes #33804wordingneutralGT1 Mercedes AMG GT3 16-19 preparation wording changed to per FIA GT3 homologation.
P2 Remove redundant effective date language and update engine table #34012wordingneutralP2 engine table wording updated; redundant effective date language removed.
P2 E&O - Correct dimensional equivalents #34038engineslowerP2 motorcycle engines: 2011+ Kawasaki restrictor reduced to 34mm, minimum weight raised to 1100 lbs; 2009+ other brands weight raised to 1100 lbs.
GT1 Sequential Transmission Weight Penalty #33503weightfasterGT1 sequential transmission weight penalty reduced from 50 to 25 lbs.
GT1 GT1 Porsche 992 #33730cars addedneutralGT1-ST Porsche 992 GT3 Cup classified with 3997cc displacement, 2950 lbs minimum weight.
P2 Request to Classify Sebeco NP01 #33378cars addedneutralSebeco NP01-EVO and Elan NP01 Mazda 2.0L MZR added to P2, 1600 lb minimum, no restrictor required.
P2 Radical spec line clarifications #33485wordingneutralP2 Radical SR3/SR4/Cup/Club Sport/Pro-Sport/PR6 removes assisted shifting requirement across all spec lines.
P2 E&O original class intent #33519wordingneutralP2 chassis rules clarified to allow composite materials in non-fully-composite construction; anti-intrusion panel attachment standardized; Stohr and converted F600 cars added with specific allowances.
P2 Update Engine Table Spec Line B.1 #33608engineunclearUnable to summarize: the change to P2 Engine Table Spec Line B.1 is not detailed in the provided text.
SM BOP for NB1 and NB2 #32309weightslowerSM Mazda MX-5 Miata 01-05 weight increases to 2450 lbs, or 2465 with alternate bore.
GT1 GT2 (TA2)/GTA Part Number Update #33315wordingneutralGT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870.
GT1 Request to Reduce Trans Am Bodywork Weight Penalty #33331weightfasterGT1 Trans Am bodywork weight penalty reduced from 100 lbs to 75 lbs.
GT1 Request for Reduction in FR9 Weight Penalty #33332weightfasterGT1 Chevrolet RO7, Ford FR9, and Dodge R7 weight penalties reduced from 50 to 25 lbs.
AS Request to add Hoosier W2 #33031tyres & wheelsneutralAS allows Hoosier W2 tyre option in addition to R7, R6, WET/H20.
AS correction of Dodge Challenger specification line #33151wordingneutralAS Dodge Challenger 08-20 adds two transmission ratio options: 2.97, 2.10, 1.45, 1.00, 0.74, 0.50 or 2.26, 1.58, 1.19, 1.00, 0.77, 0.63.
GT1 Tail lights on all GT category race cars. #32799wordingneutralGT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only.
AS Request CTS-V Spec Line Error Correction #30242weightfasterAS Cadillac CTS-V 6.0L V8 removes 50 lbs weight penalty for 295 tire size.
P2 E&O Clarification of Chassis Construction Requirements #32469wordingneutralP2 chassis construction rules clarified: fully composite or partially composite requiring composite for mobility allowed; partial composite must roll without composite parts.
P2 Clean up P2 wording #32525wordingneutralP2 classification wording cleaned up in GCR section 9.1.8.C and Contents.
P2 After Market to Aftermarket #32373wordingneutralP2 Oldsmobile cam rules clarify aftermarket manufacturer requirements; wording only.
SM Update GCR Section 9.1.7.3.A.1. #32217wordingneutralSM Majors must run authorized Penske shock and mount; Regional competitors' requirement eligibility clarified.
GT1 Mercedes Benz AMG GT3 in GT1 #31883cars addedneutralMercedes Benz AMG GT3 classified in GT1 at 3050 lbs with 40mm restrictors, prepared per FIA GT3 homologation.
GT1 Wheel Widths #32205tyres & wheelsfasterGT1 wheels: 18-inch tyres get wider rear allowance, from 13 to 14 MAX inches.
P2 Add spec line for Beasley B2 #32147cars addedneutralP2 adds Beasley B2 spec line with 1350 lbs, Mazda 12A, 40.5mm venturi, 16.5in wing.
P2 E&O Table 1 spec line wing terminology #32148wordingneutralP2 wing specs correct terminology from 'cord' to 'chord' for 16.5in single or dual element wings.
P2 E&O class name #32196wordingneutralP2 Converted F5 cars reclassified as Converted F500 cars; suspension must comply with F500 requirements, minimum width 55 inches.
GT1 Wheel Widths #31844tyres & wheelsslowerGT1 allows 17-inch wheels newly; 18-inch wheels require 50 lb penalty; maximum widths 12 front/13 rear, or 13/14 for 18-inch.
P2 E&O Engine section #31969enginefasterP2 motorcycle engines increase to 1505cc max, two-stroke to 1205cc max; automotive engines gain 50 lbs minimum weight to 1350.
AS Proposed Revisions to SCCA GCR 2021 Appendix M, Part 3 #30295wordingneutralSMG long tube headers: Borla PN 17237 discontinued, Kooks PN 11312000 and American Racing PN MT3-05134300LSNC approved alternatives.
AS specification line consolidation and correction #31846wordingneutralAS Mercury Capri (79-86) removed as individual spec line, merged into Ford Mustang (79-93) spec line.
AS correction of SMG specification line #31847wordingunclearAS Spec Mustang SMG loses 3.73 gear ratio and 355/300 mm brake specification.
AS Alternate cylinder heads for full prep engine builds - Evaluation #31851engineunclearAS Chevrolet, Pontiac, Ford full prep engines now permit alternate cylinder heads with restrictor plate ALL26180 and 1.250 inserts ALL26186 for regional competition.
P2 E&O letter #31539 – Control Area definition #31783aeroslowerP2 Control Area definition narrowed; aerodynamic attachments and vertical structures like turning vanes now prohibited.
P2 BoP adjustment effective 1-1-22 #31538wordingunclearP2 Engine Table Spec Line B.1 changed effective 1-1-22, details not provided in excerpt.
P2 E&O clarification of "Control Area" definition #31539wordingneutralP2 Control Area definition clarified: floor extensions and aerodynamic attachments on bottom or top side now explicitly included.
AS Request for adjustable Front Upper Control Arms on 4th Gen F-Body #30457suspension & brakesneutralAS Chevrolet/Pontiac Camaro & Firebird 93-02 now allow BMR AA004 or UMI 2310 adjustable front upper control arms.
AS Request Pontiac GTO tire size change #30881weightslowerAS Pontiac GTO 04-06 LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tire.
GT1 Request car classification #31032cars addedneutralGT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight.
P2 P2 CN Engine Rebuild Clarification #31000wordingneutralP2 CN Honda K20A-FD2 engine rebuild rules clarified: machining prohibition replaced with specific restrictions on balancing, porting, polishing, valve jobs, cylinder honing.
GT1 Request to Update GTA Obsolete Part Numbers #30615wordingneutralGTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix.
P2 F5 P2 Conversion #30856aerofasterConverted F5 cars in P2 minimum width reduced to 55 inches from F5 spec.
P2 Clarify minimum body width requirement #30859wordingneutralP2 clarifies minimum body width requirement between front and rear wheels for Ralt RT40, RT41, Swift 008, 014.
AS Request CTS-V Spec Line Error Correction #30242weightfasterAS Cadillac CTS-V 6.0L V8 removes 50 lbs tire size penalty, making it lighter.
AS Request to consolidate SN95 Mustang '94-'04 Mustang spec lines #30428wordingneutralAS consolidates seven SN95 Mustang spec lines into three: 94-04 including Cobra, 94-95 5.0/5.8, and 96-04 4.6L two/four valve.
AS American Sedan Transmission Rule Change Request #30595enginefasterAS Camaro/Firebird LT1/LS1 transmission code changes to 6362; Mustang GT 4.6L/5spd changes to 5.0L/6spd with 300 lbs weight reduction.
AS Correction to specifications inadvertently deleted #30691wordingneutralAS Camaro/Firebird and Mustang GT gear ratio specifications restored with alternate sets permitted.
AS weight adjustments #30700weight +50 lbsslowerAS Chevrolet Camaro & Firebird, Ford Mustang variants, Mercury Capri minimum weights increase 50 lbs across all model years.
P2 E&O tonneau cover provision in cockpit opening section #30459wordingneutralP2 tonneau covers now allowed to meet minimum dimensions; equipment attachment requirements clarified.
P2 Remove effective dates in Table 1 #30468wordingneutralP2 multiple chassis models remove effective dates from Table 1 specifications.
P2 E&O Maximum Valves Per Cylinder #30560engineneutralP2 engines limited to 4 valves per cylinder maximum across all three spec lines.
SM Updates - Obsolete Parts & BOP Parts #30438wordingneutralSM adds procedures for testing obsolete part replacements and BOP updates in sanctioned events with CRB approval.
AS AS Mustang LP 4.6 3V Classification Transmission Request #29886weightfasterAS Mustang 4.6L/5spd loses 300 lbs; 5.0L/6spd gains 56mm restrictor requirement.
AS Request CF driveshaft on CTS-V for durability improvement #30117otherneutralAS CTS-V LS6 and LS2 may now use Driveshaft Shop carbon fiber driveshaft for durability.
AS Adjustment to model years of 5th generation RP Camaro #30348wordingneutralAS Chevrolet Camaro SS V8 6.2L model years extended from 10-13 to 10-15.
P2 Add a new spec line for a 2-cycle, 3-cylinder engine up to 820cc #30272cars addedneutralP2 adds new spec line for 2-cycle 3-cylinder engine up to 820cc with 10 front and 14-15 rear wheel width.
AS Request for 2015 -2017 Ford Mustang Spec Line #29514cars addedneutralFord Mustang GT 5.0L 15-17 Restricted Preparation classified in AS with 55mm flat plate restrictor required.
AS Request Trunk lid / Rear Hatch clarification #29591wordingneutralAS underhood bracing on stock hoods, trunks, and rear decks may be modified or removed.
AS Common Weight for CTS-V Tire #29759weightfasterAS Cadillac CTS-V 04-07 with 295 tire drops to 3450 lbs; Camaro SS V8 10-13 275 tire removed; Challenger 08-20 gains 315 tire option at 3600 lbs.
AS Correction to specifications inadvertently deleted #30041weightfasterAS Camaro & Firebird (93-02) and Mustang GT (05-14) specifications restored with 200 lb weight reduction for permitted heads.
AS Request Additional Engine Options for Dodge Challenger Spec Line #29543engineslowerAS Dodge Challenger 08-20 gains 6.1L and 6.4L V8 options; 5.7L weight rises to 3500 lbs on 295 tyres, 3600 on 315 tyres.
AS Rule simplification spec line communization #29824wordingfasterAS Camaro/Firebird (93-02) and Mustang Coupe GT (05-14) consolidated into single specs with 100 lb and 300 lb weight reductions respectively.
P2 Balance of Performance adjustments effective 01-01-2021 #29822inductionfasterP2 Honda K20A-FD2 intake restrictor reduced from 55mm to 50mm, making cars faster.
SM Radiator E&O Clarifications #29294wordingneutralSM aftermarket radiators must mount in original location, maintain core plane, require no body modifications, block openings, keep one OEM fan in stock location; 1990-1997 cars may install upper radiator seal NA75-50-OK7A.
GT1 GT Category Wording #29193wordingunclearGT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line.
P2 E&O clarification of P2 rear wing requirements #29205aeroneutralP2 rear wing requirements clarified: standard wing 6×12 inches, end plates 14-inch square; alternate 110cm width wing 9×18 inches, end plates 14×18 inches.
AS Dodge Challenger AS Spec Line Clarification #28698engineslowerAS Dodge Challenger 5.7L V8 gets iron block requirement, 10.5:1 compression max, intake valve 12.7 mm, exhaust 12.3 mm, intake duration 188°, exhaust duration 205°.
AS Dodge Challenger AS Spec Line Clarification #2 #28699wordingneutralAS Dodge Challenger 08-14 rear spoiler part number changes from 1GL20RXF to 1GL20TZZAB.
GT1 Request to Allow New Trans Am Legal Engines in GT1 #29002engineslowerGT1 adds Trans Am spec engines: Chevrolet R07, Ford FR9, Dodge R7, each with 50 lbs. weight penalty.
SM Modifications to prevent failures of Rear Brake Caliper Pin #28953suspension & brakesneutralSM rear brake calipers may use single bracket under upper retaining bolt to prevent pin failure.
AS Support for R-Type Specification Tires #27450tyres & wheelsunclearAS class pursues specified list of eligible tires; details of tire changes not provided in letter.
AS Spec Tire Request #27519tyres & wheelsunclearAS class pursuing specified list of eligible tires; details pending further communication.
AS Restrictor Plate Change for RP 2011+ Mustang with Coyote Engine #27675wordingunclearNo restrictor plate change implemented; 2021 AS Mustang Coyote under evaluation.
AS 2005-2009 Restricted Prep 4.6 3V #27908engineunclearAS 2005-2009 Restricted Prep 4.6 3V now permits conversion to 2 valve configuration.
AS Request for 2005-2009 Restricted Prep 4.6 3V Parts #27909wordingunclearAS 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 #28030cars addedunclear2010-2014 Camaro reclassified to AS; full preparation classification approved effective 2020-07-01.
AS Cylinder Heads #28696wordingunclearAS class cylinder head replacement options under review; implementation planned for 2021 season.
AS Request for Max Rotor Diameter Change #28748suspension & brakesfasterAS Mustang, Camaro, Firebird, Capri max brake rotor diameter increases from 12.2 to 13.1 inches.
AS Request increase rotor diameter #28797suspension & brakesneutralAS rotor diameter increase approved; see Fastrack letter #28748 for details.
GT1 TA2 Gurney flap wicker clarification #28874wordingneutralTA2 Gurney flap wording clarified: terminology standardized to 'Gurney flap', height limits and thickness specifications remain 0.50 inch / 0.625 inch or 0.375 inch / 0.0625 inch depending on configuration.
GT1 STO Gurney flap wicker clarification #28883wordingneutralSTO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules.
GT1 GT1 Gurney flap wicker clarification #28886wordingneutralGT1 Gurney flap wicker clarification: terminology standardized from lips/tabs/wicker to flaps throughout specifications.
P2 Classify Elan NP01 in P2 Table 1 #28812cars addedneutralElan NP01 classified in P2 Table 1 as Spec Line car with 2000cc displacement and P2 Engine Table restrictor.
AS weight adjustments for 2020 season #28785weight -50 lbsfasterAS Chevrolet/Pontiac Camaro & Firebird (82-92) loses 50 lbs, to 3500.
P2 SCCA Enterprises ESR / P2 engine restrictor testing #28669engineneutralP2 Enterprises Sports Racer adds 55mm flat plate intake restrictor Part # WM303013 as alternative to SIR.
P2 Add ESR inlet restrictor #27869inductionslowerP2 Enterprise Sports Racer 2.3L engine now requires SIR or Flat Plate restrictor sized in 0.5mm increments.
P2 Request for Fly by Wire Rule Wording Change #28247wordingneutralP2 fly-by-wire throttle control wording clarified: stock ECUs with drive-by-wire must activate original throttle shaft mechanism.
AS Rear Trailing Arms #28007suspension & brakesneutralAS 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 #28010weightfasterAS Ford and GM full-prep cars get 200 lb weight reduction, up from 150 lb.
AS 05-10 Mustang with HR cam classification #28226cars addedneutral05-10 Ford Mustang Coupe GT 4.6L OHC classified AS with 3200 lbs minimum weight, HR cam restricted prep.
AS 10-15 Camaro Full Prep classification #28227cars addedneutralAS 10-15 Chevrolet Camaro Full Prep classified with 3400 lbs base weight, over 313 CID engine 3700 lbs maximum.
GT1 Windshield Clips #27323wordingneutralGT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications.
GT1 Request to classify the Ford Coyote 3rd Gen OEM #27146cars addedneutralGT2/ST Ford 5.0L Coyote 3rd Gen OEM added at 3200 lbs with Boss intake manifold permitted.
GT1 Request Factory Five Daytona coupe classification #26308cars addedneutralFactory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs.
GT1 Request to Adjust Transmission Penalty #27750weightfasterGT1 sequential shifting transmission weight penalty reduced from 75 to 50 lbs.
GT1 Request to Reduce Additional Weight for 18 #27751weightfasterGT1 non-18-inch-wheel cars now get 18-inch wheels with 50 lb penalty, down from 100 lb.
GT1 Request for Five Star Nascar Compliant Bodywork #27756cars addedneutralGT1 Spec Lines allows 5 Star NASCAR Camaro 2018+ body for General Motors Corporation.
P2 Request for addition of BMW Engine in P2 Engine Table #27821cars addedneutralP2 adds BMW to motorcycle-based engine options in 4-cycle line alongside Kawasaki, Suzuki, Yamaha, Honda.
AS Request to add SMG to 9.1.6.B.1 AS Intent #27140cars addedneutralAS Spec Mustang (SMG) added as Restricted Prep class.
P2 Update Engine Table Line E notes #27414inductionslowerP2 Honda K20A-FD2 non-composite chassis must use 55mm flat plate intake restrictor at 1500 lbs minimum weight.
P2 Update P2 Engine Table spec lines to reflect 3/1/2019 #27254inductionslowerP2 motorcycle engines: Stock restrictor 36.5mm to 35mm, modified 37.5mm to 34mm; B.5 restrictor 37.5mm to 33mm. All weights increase 25 lbs.
AS Request Ride Height Clarification #26598wordingneutralAS class minimum ride height clarified to 5 inches measured at rocker panel, excluding seams and cladding.
GT1 Clarify Trans Am Legal Bodywork and Wing #26953aerofasterGT1 allows Trans Am rear wing, 12" chord, 72" span, 1/2" wicker, 100 sq in endplates, no weight penalty.
P2 E&O Transmissions #27006otherslowerP2 cars limited to power application on maximum two wheels, effective 2019-07-01.
P2 Request to restrict all cars #26246weightslowerP2 Enterprise minimum weight increases to 1375 lbs; peak horsepower of sealed ESR engine reduced per CRB specification.
AS Request to Revert to 2017 Weights #25885weightfasterAS Ford Mustang (79-93) 313 CID and under loses 100 lbs to 3150; over 313 CID loses 100 lbs to 3450.
GT1 Request GTX Fuel injection for previous GT-1 tube frame cars #26141inductionfasterGTX tube frame cars gain fuel injection with 90mm maximum throttle body size.
GT1 Request to Classify Ligier JS2 R #26535cars addedneutralLigier JS2 R classified in GTX, no performance parameters specified in filing.
GT1 Request Ride Height Clarification #26600wordingneutralGT1 and GT2/GT3/LITE ride height requirements removed from GCR sections 9.1.2.D.5.a.1 and 9.1.2.F.7.b.
P2 Change Engine Table Lines B.1 & B.5 #25777inductionslowerP2 stock engine restrictor shrinks to 35.0mm and weight rises to 1025 lbs; modified engine restrictor to 34.0mm, weight to 1125 lbs; line B.5 restrictor to 33.0mm, weight to 1185 lbs.
P2 Change Line A.1 restrictor size #26429inductionslowerP2 Line A.1 restrictor reduced from 40mm to 38mm.
SM Request to allow aftermarket fuel filters. #26370wordingneutralSM fuel pump and filter must be Mazda or OEM Equivalent part.
AS SMG Mustang eligibility in American sedan #26224cars addedneutralAS Spec Mustang (SMG) newly classified with 107.1 wheelbase, 3.73 gears, 355mm front brakes, 300mm rear.
SM Request 99-00 replacement Wire harnesses #25602wordingneutralSM 1999-2000 model year cars may use replacement Mazda ECU and injector harnesses, unmodified.
SM Organize and Clarify 9.1.7.C.1.o. #25913wordingneutralSM electrical rules reorganized and clarified; alternator external regulation now prohibited except via OEM ECU/kill switch.
SM Strike Tire Tread Language #26123wordingneutralSM removes tire tread protrusion beyond fender opening requirement from GCR 9.1.7.C.5.
GT1 GTX Homologation table update #26034cars addedneutralGTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified.
P2 Request to Allow 1345cc Hayabusa Engines for Spec Line P2 Cars #25595enginefasterP2 Spec Line cars now allow 1345cc Hayabusa stock engines at 1050 lbs with 30mm restrictor.
P2 Change CN inlet restrictor implementation date #25816wordingneutralP2 Group CN Honda K20A-FD2 55mm restrictor implementation delayed from 1/1/2019 to 3/1/2019.
P2 Clarify Honda K20A-FD2 parts requirement #25950inductionslowerP2 Honda K20A-FD2 in CN chassis must use stock intake manifold with 64mm throttle body and 55mm restrictor at 1500 lbs minimum weight.
Best is the class's fastest lap in that event's qualifying or race sessions, with the driver who set it, how many cars set a time that session and how close the top five were; a best from fewer than three cars is greyed. With two or more classes, "vs" is the gap of each class's best to the first class's at the same event. "% of SM" is the class's best as a share of SM's best at the same event (100% is level, less is quicker): weather and track condition move every class together, so this compares across years where the raw times do not. It still breaks when SM's own field changes or one session was wet and another dry. Newest event first. The coloured figure under each value is the change from the previous event that has one (green is quicker, red slower). Whole laps only, so events with different sector layouts still compare. Weather and track condition are not accounted for.