Mandated Spec Corvette specifications
Eligible cars are 1997 to 2004 C5 models base coupe, FRC and Z06
• Minimum weight - 3250 lbs. **** UPDATE 2/6/18 MIN Weight has change to 3200 lbs. due to most vehicles using excessive ballasts to make min weight. Official Min Weight is now 3200 lbs with driver, directly AFTER you pull off the track after the race. • Removal of carpet and insulation, AC/heating, windows, radio, passenger seat, parking brake permissible.
• Engines must be stock LS6 or LS1
• *** 2017 Season: LS1 slated as benchmark engine power. LS6 will run with restrictor plate to bring power to LS1 level.
• *** Under review for 2018 season. LS1 is upgradeable to LS6 intake, heads, cam and oil pump
• Exhaust manifolds must be stock. Removal of catalytic converters and exhaust after manifolds is open to modification
• Tuning for race gas and use of race gas is not permissible
• Katech Tensioner allowed to prevent belt walking. 
. Stock engine ECU mandatory
• Catch cans permissible
• Z06 oil pan or Improved racing baffle kit recommended P/N EGM-202
• Dyno reports required for each car. All engines are stock LS1. No power or efficiency modifications allowed to LS1 engine for 2017 season
• Removal of non-essential wiring OK
• Bigger radiator, engine, tranny and diff coolers are allowed for ruggedness and reliability
Drive Train
• All components must be stock.
• No changes to OEM differential, clutch, flywheel, torque tube/drive shaft and gear box are allowed
• Max gearing allowed is factory 3.42 gears.
• Driver has choice of MN6 or MN12 manual transmission
• Rubber Guibo bushings on driveshaft may be upgraded to billet or other for reliability.
• No short shifter modifications allowed, although C6 factory shifter is permissible
• Aftermarket shift knob permissible
Alignment settings
Front settings
• camber must be -3.0 maximum (+-.2 variance allowed)
• Toe out 1/16 maximum (+-1/16 variance allowed)
• Caster is -6.5 maximum(+-.5 variance allowed)
Rear settings
• camber must be -1.2 maximum (+-1/16 variance allowed)
• Toe in 3/16 maximum (+-1/16 variance allowed)
Rake and ride height on both sides of the car
• Front ride height just in front of factory metal frame rail jacking point is 4.5”
• Rear ride height just in back of factory metal frame rail jacking point is 4.75”
• Shocks are AFe Control single adjustable SPEC CORVETTE coil-overs
• OEM monoleaf springs and shocks are permissible, including T1
• A-arm bushings upgradeable to monoball, delrin, or polyurethane.
• OEM rubber bushings in factory A-arms are permissible
Sway Bars
• AFe SPEC Corvette sway bars, brackets, pillows and end-links
• OEM C5, Z06, and T1 are permissible
• SKF racing hubs with ARP extended studs optional
• OEM hubs are permissible, but not advised. OEM hubs are guaranteed to crack at the flange under frequent racing conditions.
Upright options
• Stock C5 uprights
• Stock C6 uprights
Official Big Brake kit of SPEC CORVETTE Wilwood Brakes
• Wilwood 6 piston P/N 140-14557-N with hose kit P/N 220-8176
• Race pad compounds are permissible
Official Race Pads and rotors of SPEC CORVETTE Powerstop
• Powerstop "Trackday" race pads
• Front Pads P/N PST-731
• Rear Pads P/N PST-732
• Front Rotors P/N AR8259XPR-HC
• Rear Rotors P/N AR8261XPR-HC
• Stock C5 or C6 OEM brake calipers allowed
• Upgrade to Z51 rotors and brackets permissible, front and rear
• Race pad compounds are permissible
• Stainless steel brake lines are permissible
• Race brake fluid advised
• For durability and economy a two-piece aftermarket rotor is acceptable as long as it is the same size and a steel rotor (No Carbon!)
• Stainless steel caliper pistons are permissible to upgrade factory C5/C6 calipers
• Aftermarket brake ducting is permissible
• Wheels must be 18" diameter and a minimum 10" width and maximum 11" width on all four corners
• OEM rear 10.5” x 18” Z06 Speedlines are permissible
• Wheels must weigh 20 lbs. minimum
• Aftermarket wheel studs and lug nuts OK
Official Tires of SPEC CORVETTE Falken Tire 615K+
• Tires are 315/30x18 on all four corners
• All vehicles MUST RUN the series specific tire Falken 615K+
Other allowed modifications
Official Hood Vents of SPEC CORVETTE Trackspec Motorsports C5 T1 hood vent kit in specified location
• Trackspec Motorsports 3” rear spoiler
• Change of steering wheel with quick-release 
Required equipment
• The safety rules within the SCCA GCR are the over-riding guidelines with regards to safety specifications listed below
• Removal of airbags
• 10 lb. fire system mandatory
• Electrical cut-off switch
• FIA race seat, halo protection strongly recommended
• HANS or equivalents
• FIA or SFI harness within date requirements
• Window net required
• Tow hooks front and rear required
• Cage must meet SCCA spec's for T1
• Headlights and wipers must work
Specifically disallowed
• Race gas 

Any modifications not specifically approved above are not allowed and will result in likely disqualification. So don’t try to get away with unapproved modifications.