A variety of classes are available to fit your particular car.
- P0: Piston engines with 3501cc displacement and up
- P1: Piston engines with 2500cc to 3500cc displacement; or 13B rotary engines.
- P2: Piston engines with 1650cc through 2499cc of displacement and 12A rotary engines.
- P3: Piston engines with 1649cc of displacement or less.
- SR: Sports Racer class. Open only to cars eligible to compete in ICSCC/SCCA Sports Racing classes.
All engine displacement measurements exclude an overbore allowance of 1.2 mm (0.047 inches). Any car with a turbo or supercharger shall multiply their displacement by a factor of 1.4.