AS vs SRF vs T4 pace at Michelin Raceway Road Atlanta
Quickest here:AS 1:34.231 Tom Ellis, Super Tour Mar 2021 qualifying · T4 1:38.841 Jonathan Neudorf, Super Tour Mar 2023 qualifying
ASSRFT4solid race · dashed qualifying · slower is lower
ASSRFT4solid race · dashed qualifying · each class's best lap as a share of AS's at the same event (the reference class, changeable above); 100% is level, higher is quicker
Event
AS
SRF
T4
Qual best
Race best
Trap
Qual best
Race best
Trap
vs AS
% of AS
Qual best
Race best
Trap
vs AS
% of AS
Super Tour Mar 2026 ST26MAR062026-03-06
2:28.404Michael Kamalian · only car+52.937s (+55.45%)
1:34.642Michael Kamalian · only car-0.709s (-0.74%)
140.9Michael Kamalian+2.4 mph (+1.7%)
1:40.673Kevin Fryer · fastest of 5 · top 5 within 7.2s+0.697s (+0.70%)
1:40.736Ayden Rose · fastest of 5 · top 5 within 8.6s+1.082s (+1.09%)
121.0Angelica Sprehe+8.3 mph (+7.3%)
+6.094squal -47.731s
106.4%qual 67.8%
36 rule changes (AS: 11, SRF: 4, T4: 21)5 cars added · 5 induction · 5 weight · 2 suspension & brakes · 2 tyres & wheels · 1 aero · 1 engine · 1 removed · 5 wording · 9 other · AS Spec Lines reorganized for 2026; detailed chassis, engine, weight, wheelbase, tire and brake specifications moved to main rules and engine build sheets. · AS GM LM7 5.3L gains Edelbrock 71187 intake manifold, MSD 6014 ignition box, Holly 4776 carb option under full prep spec line. · AS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm. · 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. · 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. · 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.showhide
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.
T4 Allow Alt Bushing Material in Toe Links #39607suspension & brakes
AS Restrictor Plate Change for Gen 2 Ford Coyote Engine #39501inductionslower · inductionAS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm.
T4 Alternate Placement of Fuse Panel and Electronics Request #39370other
AS 1994 Mustang Spec Line Request #39104engineadded · engineAS Ford Mustang GT 94-04 Restricted Prep Engine now permits Ford Motorsport M-6250-F303 camshaft.
AS Errors and Omission #38055inductionslower · inductionAS Ford Mustang GT 5.0L 15-17 flat plate restrictor reduces from 67mm to 64mm.
AS Request to Add LS1/LS6 Intakes for 5.3L Truck Engine EnO #38197cars addedaddedAS LS1/LS6 intakes added for 5.3L truck engine: part numbers 12561269 and 88894095.
T4 Correct Ring and Pinion Ratio to T3, Sorry I Mean T4 3.7 V6 Stang #38041wording
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.
1:35.467Thomas J Ellis · fastest of 4 · top 4 within 2.7s-8.834s (-8.47%)
1:35.351Thomas J Ellis · fastest of 4 · top 4 within 1.1s-24.914s (-20.72%)
138.6James Jost+8.6 mph (+6.6%)
1:39.976Ethan Barker · fastest of 4 · top 4 within 1.9s-0.527s (-0.52%)
1:39.654Marc Cefalo · fastest of 4 · top 4 within 2.7s-1.425s (-1.41%)
112.8Robert Spence-1.3 mph (-1.1%)
+4.303squal +4.509s
104.5%qual 104.7%
58 rule changes (AS: 12, SRF: 6, T4: 40)12 weight · 10 cars added · 7 engine · 7 tyres & wheels · 5 suspension & brakes · 2 aero · 2 induction · 1 removed · 2 wording · 10 other · 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. · AS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options. · FE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure. · AS adds 2018-23 Ford Mustang GT 5.0L at 3600 lbs, 275 tire, 60mm restrictor, optional Brembo front brakes. · AS Chevrolet Camaro 1LE (2016-) added with 3600 lbs minimum weight, 275 tires, 60mm restrictor, 345/338mm brakes. · AS Chevrolet/Pontiac Camaro & Firebird 82–92 5.7L LS1 classified: 3200 lbs, 13.1×1.27 disc brakes, 17 in max wheel, 65 mm restrictor, SLP intake lid permitted. · AS Chevrolet Camaro, Firebird, and Ford Mustang now permit Flo Tek cylinder heads in multiple generations. · AS Camaro, Firebird 93-02 and GTO 04-06 add approved LS1 connecting rod part numbers to Notes. · AS Cadillac CTS-V, Chevy Camaro SS V8, Dodge Challenger, Ford Mustang GT 5.0L, Pontiac GTO allowed 11" wheels until 3/1/25.showhide
AS Race memo #37902wordingwordingAS removes 'Any ECM maybe used' note from five Cadillac and Chevrolet/Pontiac V8 Restricted Prep models.
T4 Request to Classify Club Spec in Appropriate Touring Classes #37523cars added
AS Increase Coyote Engine Restrictor to 80mm #36177enginefaster · engineAS Ford Mustang and Cobra Coyote engine restrictor increases to 80mm from 67mm or 64mm.
AS Performance Pack for 2015+ Mustang #36867enginefaster · engineAS Mustang GT 05-14 Restricted loses 300 lbs engine; 15-17 and 2018+ models lose 61mm and 60mm restrictors respectively.
AS Gear Ratios #37131otheraddedAS class: multiple American muscle cars gain additional allowed gear ratio options across model years and prep levels.
AS ECU specs for LS engine #37208engineadded · engineAS LS-engine cars gain ECU freedom: CTS-V, Camaro, Firebird (70–02) and Camaro SS may use any ECM.
T4 Remove spec lines that have expired #37269induction
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.
T4 Allow OEM Front Spoiler 06-08 Miata in T4 #35941aero
T4 GCR ERROR - letter not properly applied to GCR #35999weight
AS Restricted Prep Aftermarket Parts Request #35682otheraddedAS Camaro, Firebird 93-02 and GTO 04-06 add approved LS1 connecting rod part numbers to Notes.
AS Allowance of 11 #35824tyres & wheelsfaster · tyres & wheelsAS Cadillac CTS-V, Chevy Camaro SS V8, Dodge Challenger, Ford Mustang GT 5.0L, Pontiac GTO allowed 11" wheels until 3/1/25.
2:00.265Phillip Waters · only car+24.272s (+25.29%)
130.0Phillip Waters-13.7 mph (-9.5%)
1:40.503Marc Cefalo · fastest of 6 · top 5 within 1.5s+1.662s (+1.68%)
1:41.079Kevin Fryer · fastest of 6 · top 5 within 3.0s+0.623s (+0.62%)
114.0Angelica Sprehe-9.4 mph (-7.6%)
-19.186squal -3.798s
84.0%qual 96.4%
35 rule changes (AS: 8, SRF: 6, T4: 21)8 suspension & brakes · 6 weight · 3 cars added · 3 induction · 3 tyres & wheels · 3 wording · 9 other · 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… · 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.showhide
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…
T4 Inclusion of similar car. (CLK 320) #34626other
AS Crate Motor Part Numbers #32944wordingwordingAS crate motor part number specification clarified; both CT400 P/N-19370604 and 19370604 engine assemblies permitted for GM vehicles.
AS Request wheel size change #33007tyres & wheelsfaster · tyres & wheelsAS Ford Mustang GT 5.0L (15-17) Restricted maximum wheel diameter increases to 19.0 inches.
AS Alternative Upper Front Control Arms for Dodge Challenger #33352wordingwordingAS Dodge Challenger 5.7L/6.1L/6.4L V8 allows alternate front upper control arms; SPC-66045 spec part removed.
AS Front Brake Caliper Adapters for Dodge Challenger #33353otherotherAS Dodge Challenger 5.7L/6.1L/6.4L V8 now allows alternate front brake calipers with adaptor brackets for component compatibility.
T4 Rules Clarification for Mazda RX8 Spec Line #34395weight
T4 Mazda OEM LSD was letter 32655 #32933weight -25 lbs
T4 Another 2022 BRZ/86 T3 request #32945weight +225 lbs
AS Request to add Hoosier W2 #33031tyres & wheelsadded · tyres & wheelsAS adds Hoosier W2 wet tyre option alongside R7, R6, WET/H20.
AS correction of Dodge Challenger specification line #33151cars addedaddedAS Dodge Challenger 08-20 gains two transmission ratio options: 2.97–0.50 or 2.26–0.63.
1:36.346Gregory Eaton · fastest of 3 · top 3 within 7.0s+2.115s (+2.24%)
1:35.993Gregory Eaton · fastest of 2+1.259s (+1.33%)
143.6Gregory Eaton-19.3 mph (-11.9%)
1:40.563Ethan Barker · fastest of 6 · top 5 within 6.1s-0.030s (-0.03%)
1:41.214Richard Astacio · fastest of 6 · top 5 within 3.0s+1.095s (+1.09%)
118.4Angelica Sprehe-1.3 mph (-1.1%)
+5.221squal +4.217s
105.4%qual 104.4%
38 rule changes (AS: 11, SRF: 5, T4: 22)9 weight · 5 suspension & brakes · 4 engine · 4 tyres & wheels · 3 cars added · 2 induction · 1 removed · 7 wording · 3 other · SMG Long Tube Headers: Borla PN 17237 discontinued, approved alternatives American Racing MT3-05134300LSNC or Kooks PN 11312000. · AS Mercury Capri 79-86 removed as separate spec line, merged into Ford Mustang 79-93 spec line. · AS Spec Mustang SMG Restricted Prep removes 3.73 gear ratio and 355/300 brake disc sizes. · AS Camaro, Firebird, Mustang full prep engines: alternate GM and Ford Performance cylinder heads permitted regionally with Allstar restrictor ALL26180. · AS Chevrolet/Pontiac Camaro & Firebird 93-02 gains BMR AA004 or UMI 2310 adjustable front upper control arms. · AS Pontiac GTO 04-06 Restricted Prep minimum weight rises: LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tires. · 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.showhide
T4 Reply to letter #31486/29879 T2-T4 Grill openings #31935suspension & brakes
T4 Request Allowances for 2005 - 2010 Mustang #31624wording
AS Proposed Revisions to SCCA GCR 2021 Appendix M, Part 3 #30295wordingwordingSMG Long Tube Headers: Borla PN 17237 discontinued, approved alternatives American Racing MT3-05134300LSNC or Kooks PN 11312000.
AS specification line consolidation and correction #31846cars addedremoved · cars addedAS Mercury Capri 79-86 removed as separate spec line, merged into Ford Mustang 79-93 spec line.
AS correction of SMG specification line #31847wordingremovedAS Spec Mustang SMG Restricted Prep removes 3.73 gear ratio and 355/300 brake disc sizes.
AS Alternate cylinder heads for full prep engine builds - Evaluation #31851engineadded · engineAS Camaro, Firebird, Mustang full prep engines: alternate GM and Ford Performance cylinder heads permitted regionally with Allstar restrictor ALL26180.
T4 Reply to letter 29879 T2-T4 Grill Openings #31486suspension & brakes
T4 Please Adjust 98-00 BMW 323 Min Weight to Reflect Current Class #31595weight -200 lbs
T4 Consolidate 12-13 and 14-15 Honda Civic Si spec lines for T4 #31596removed
T4 Request to clarify radiator hoses #31682wording
T4 Adjust Honda FWD in T4 to encourage more Drivetrain Diversity #31472tyres & wheels
T4 Touring 4 BOP adjustments for 2022 #31482weight -175 lbs
T4 Request to Classify 2014 VW Jetta 1.8t TSI #30436cars added
AS Request for adjustable Front Upper Control Arms on 4th Gen F-Body #30457otheraddedAS Chevrolet/Pontiac Camaro & Firebird 93-02 gains BMR AA004 or UMI 2310 adjustable front upper control arms.
AS Request Pontiac GTO tire size change #30881weightslower · weightAS Pontiac GTO 04-06 Restricted Prep minimum weight rises: LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tires.
SRF SRF Update Maintenance, Repairs and Seals #30961engine
T4 Wrong Part Number on 320i Spec Line #30645wording
AS Request CTS-V Spec Line Error Correction #30242weightfaster · weightAS Cadillac CTS-V 6.0L LS6 removes 295-tire 50 lb penalty.
AS Request to consolidate SN95 Mustang '94-'04 Mustang spec lines #30428wordingwordingAS consolidates seven SN95 Mustang '94-'04 spec lines into three unified lines by model year and engine.
AS American Sedan Transmission Rule Change Request #30595enginefaster · engineAS Camaro/Firebird LT1 and LS1 transmission changed to TUET1 6362; Mustang GT 4.6L/5spd to TUKT16901, loses 300 lbs.
AS Correction to specifications inadvertently deleted #30691wordingwordingAS Camaro & Firebird and Mustang GT gear ratio specifications restored with alternate sets permitted.
AS weight adjustments #30700weight +50 lbsslower · weightAS Camaro, Firebird, Mustang, and Capri all gain 50 lbs minimum weight across seven model year variants.
1:34.231Tom Ellis · fastest of 7 · top 5 within 7.4s
1:34.734Tom Ellis · fastest of 8 · top 5 within 5.6s
163.0Tom Ellis
1:40.593Thomas Fowler · fastest of 8 · top 5 within 3.1s
1:40.119Thomas Fowler · fastest of 8 · top 5 within 2.1s
119.7Richard Dickey
+5.385squal +6.362s
105.7%qual 106.8%
92 earlier rule changes on record, in force before Super Tour Mar 2021 (from 2019)16 cars added · 15 weight · 12 suspension & brakes · 7 engine · 7 tyres & wheels · 2 aero · 2 induction · 15 wording · 16 other · 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. · 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 · 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. · AS Spec Mustang (SMG) added as Restricted Prep class. · AS class ride height minimum clarified: five inches measured at rocker panel, excluding seams and stock effects. · AS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450. · AS adds Spec Mustang SMG classification with 107.1 wheelbase, 3.73 gears, 355mm front and 300mm rear brakes.showhide
AS AS Mustang LP 4.6 3V Classification Transmission Request #29886enginefaster · engineAS Mustang 4.6L 5spd gains cold air intake freedom; 5.0L 6spd now requires 56mm flat plate restrictor.
AS Request CF driveshaft on CTS-V for durability improvement #30117otheraddedAS CTS-V 5.7L LS6 and 6.0L LS2 may use Driveshaft Shop P/N GMCTSV2-C carbon fiber driveshaft.
AS Adjustment to model years of 5th generation RP Camaro #30348cars addedaddedAS Chevrolet Camaro SS V8 6.2L Restricted Prep model years extended from 10–13 to 10–15.
T4 Change part numbers on BRZ, FRS lines in T4 #30104wording
T4 T4 Mustang Axle Ratio and Wheels #30149tyres & wheels
AS Request for 2015 -2017 Ford Mustang Spec Line #29514cars addedaddedAS Ford Mustang GT 5.0L 15-17 Restricted added to Spec Line with 3600 lbs minimum weight, 55mm restrictor, 18×10 wheels, 295 tires.
AS Request Trunk lid / Rear Hatch clarification #29591wordingwordingAS underhood bracing on stock hoods, trunks, and rear decks may be modified or removed.
AS Common Weight for CTS-V Tire #29759weightfaster · weightAS Cadillac CTS-V 04-07 with 295 tire drops to 3450 lbs; Camaro SS V8 10-13 and Challenger 08-20 specs removed.
AS Correction to specifications inadvertently deleted #30041cars addedaddedAS Camaro & Firebird (93-02) and Mustang GT (05-14) specifications restored with weight minimums 3250–3500 and 3350–3600 lbs respectively.
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.
SRF SRF Shocks, Springs and Ride Height. #29688suspension & brakes
T4 Post Runoffs Feedback for T4 #29752tyres & wheels -50 lbs
AS Dodge Challenger AS Spec Line Clarification #28698engineslower · engineAS Dodge Challenger 5.7L V8 now requires iron block instead of aluminum, compression to 10.5:1 max, intake valve 12.7 mm, exhaust 12.3 mm, intake timing 188 degrees, exhaust timing 205 degrees.
AS Dodge Challenger AS Spec Line Clarification #2 #28699aeroaeroAS Dodge Challenger 08-14 rear spoiler: 1GL20RXF replaced with 1GL20TZZAB; 82211606 still permitted.
T4 Scion FRS Solo Spec Coupe Gear Ratio #29021other
AS Support for R-Type Specification Tires #27450wordingunclearAS class pursuing specified list of eligible tires; list details unclear from text provided.
AS Spec Tire Request #27519wordingunclearAS class tire eligibility list under development; no specifications changed yet.
AS Restrictor Plate Change for RP 2011+ Mustang with Coyote Engine #27675wordingunclearAS Coyote Mustang restrictor plate under review for 2021; no change effective yet.
AS 2005-2009 Restricted Prep 4.6 3V #27908engineadded · engineAS Restricted Prep 4.6 3V now permits conversion to 2 valve configuration.
AS Request for 2005-2009 Restricted Prep 4.6 3V Parts #27909engineadded · engineAS Ford Mustang Coupe GT 4.6L 3V Restricted Prep now permits Ford Performance camshaft kit P/N M-6550-3V.
AS Request for Full Preparation Classification for 2010-2014 Camaro #28030wordingunclear2010-2014 Camaro remains classified in AS; no specification changes.
AS Cylinder Heads #28696wordingunclearAS class cylinder head supplier discontinuation; replacement option pending for 2021 season.
AS Request for Max Rotor Diameter Change #28748otherfasterAS Mustang, Capri, Camaro, and Firebird maximum brake rotor diameter increased from 12.2 to 13.1 inches.
AS Request increase rotor diameter #28797wordingunclearunclear
T4 Request for 12-13 and 14-15 Honda Civic Springs #27848suspension & brakes
T4 Request to Clarify T4 05-10 Mustang Spring Allowance #27899suspension & brakes
AS Rear Trailing Arms #28007suspension & brakesadded · suspension & brakesAS rear trailing arms may be replaced with tubular arms maintaining stock length and axle location purpose only.
AS Weight reduction for cars running iron heads #28010weightfaster · weightAS Ford and GM full prep cars get increased weight reduction from 150 to 200 lbs.
AS 05-10 Mustang with HR cam classification #28226cars addedadded05-10 Ford Mustang Coupe GT 4.6L OHC classified AS with 3200 lbs minimum weight, HR cam permitted.
AS 10-15 Camaro Full Prep classification #28227cars addedadded10-15 Camaro Full Prep classified AS with 3400 lbs base weight, 3700 lbs over 313 CID, specific head castings and Edelbrock heads permitted.
T4 Request to Allow Brake Upgrade on T4 Mustang #27329suspension & brakes
T4 Please Switch the Solstice GXP as Specified in T2, to T3 #27413weight -50 lbs
T4 Request to Classify all Mazda RX8 Models in T3/T4 #27606cars added
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 #25885weightfaster · weightAS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450.
T4 Request to allow piggy back ECU on 2000 Mazda Protégé #26085engine
T4 Request helper spring as optional #26678suspension & brakes
T4 Request to classify 2000 - 2001 BMW 323 #25096cars added
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.
T4 2012-2015 Honda Civic Si Performance Request #26129suspension & brakes
T4 Errors, Omissions, and Updates (Various) #22414weight
T4 Request for Adjustments to fiat 124 specline #25371induction
T4 Add Clarification to Spec Car Classifications Vehicle Spec #25774weight
T4 Clarify Subframe Bushings Permitted for T2-T4 #25800suspension & brakes
T4 Consider Solo SSC cross over classification into T4 #25802cars added
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 AS" is the class's best as a share of AS'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 AS'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.