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Pro 24


General Safety

  •  All vehicles must conform with general NHRA safety rules.


  •  Must have an import body or a domestic sport compact body. Any year vehicle is allowed. Lightweight components are limited to hood, front fenders, decklid, hatches, sunroofs, wings, ground effects, and bumpers only. Roof, Quarter panels, and doors must remain steel. One-piece front ends are not permitted. FWD cars are permitted to run widened three-piece front ends. No body parts may be removed during competition.


  • All cars must retain complete stock chassis, floorboard, firewall, and frame rails. Notching of chassis for clearance is permitted. Aftermarket “K” members are permitted.
Suspension: All cars must utilize stock front and rear suspension and mounts. Aftermarket front control arms, rear control arms, and sub-frame connectors are permitted. Aftermarket struts and shocks are permitted (electronic adjustable shocks are prohibited).


  • All vehicles must utilize four wheel braking, secondary staging brakes, and split systems permitted. Electric vacuum pumps are only permitted for brake assist and must be solely connected to the brake booster alone.


  • Headlights and brake lights are required (one headlight may be removed for induction).


  • All windows must be OEM glass (Rear window only may be made of lexan).


  • Stock dashboard and full interior from front seats forward is required (passenger seat may be removed). Aftermarket seats, gauges, and interior are permitted.


  • Muffler(s) are required unless vehicle is turbocharged. Exhaust may exit anywhere.


  • Two-steps, data loggers, aftermarket ECU’s, and engine management systems are allowed.


  • Aftermarket axles, ring and pinions, final drive, spools, and differentials are permitted. Other 
OEM or aftermarket center sections and rear-ends may be replaced only if is a direct bolt in. IRS suspension cars may convert to straight axle only if it is a direct bolt in.


  • Manual or Auto transmissions are permitted. Any style automatic transmission is permitted. Trans-brakes are prohibited. Manual transmissions are permitted to use aftermarket stock-style clutch-assisted transmissions. Sequential transmissions are prohibited. Aftermarket bell housings are permitted.


  • The use of slider, adjustable, or slipper style clutch prohibited. Three discs maximum (any type of disk material is permitted). Clutch must be manually operated by driver’s foot.


  • Shifter must be H-pattern. Strain gauges are permitted on FWD cars only. Air shifters are prohibited.

No Wheelie bars Permitted


  • Gasoline or E-85 permitted. Methanol is prohibited.

Fuel System

  • Electric fuel pumps only are permitted. Aftermarket fuel cells are permitted, and may be mounted anywhere.

Oiling System

  • Dry sump oil system or external oil pumps prohibited unless OEM equipped and engine is using complete OEM oiling system.
Engine Containment Device: Engine diaper or catch pan device to capture oil and/or debris in the event of engine and/or transmission failure mandatory. Where exhaust header passes directly under oil pan, a two piece diaper may be utilized. If a catch pan device is used, catch pan must employ minimum 2 inch high lips on all sides. Lips must be covered or curved inward, so as to contain oil in pan. Catch pan must cover entire area below the engine/transmission. Catch pan must extend from radiator support to firewall and from frame rail to frame rail. In all cases, lips must be adequate enough to contain oil in the catch pan. Should a competitor spill excessive oil from the catch pan and debris onto the track, he or she may be disqualified from further competition at the sole and absolute discretion of the event director until the catch pan is upgraded, regardless of the height of pan lips or pan design.


  • Engine must be of import origin or domestic sport compact origin. Any internal engine modifications are permitted. Motor swaps of same manufacturer or different manufacturers are allowed as long as they meet weight requirements. Aftermarket blocks are permitted.


  • Turbochargers are measured at the inducer wheel where the leading edge of the inducer wheel meets the housing. The contour from the inducer to the exducer must be continuous without steps. The use of restrictor plates, stepped inlet housings or reducers in an effort to limit compressor size opening is not acceptable. Compressor housing cannot be modified from the leading edge of the inducer to the trailing edge of the exducer. All inducer surge ports must be perpendicular to the shaft and limited in location to the leading edge of the inducer. See chart below for turbo size restrictions. All inducer surge ports must be perpendicular to the shaft and limited in location to the leading edge of the inducer. See chart below for turbo size restrictions.

Nitrous Oxide

  • Any style nitrous oxide system is permitted for combinations that allow nitrous oxide. If nitrous oxide is not permitted for your combination then bottles and solenoids must be removed from car and nitrous nozzles must be capped. See tables below to see if nitrous oxide is permitted for your combination.


  • Air intercoolers only are permitted. Water injection is permitted. Methanol injection is permitted, but must be injected into the charge pipes before the throttle body.
Induction: EFI or carburetors are permitted. Any style intake is permitted.


  • All tires are checked by sidewall designation. See slick and DOT bias ply tire size restrictions below. 
FWD: Maximum size slick or DOT bias ply tire is 24.5” x 9.5″ or 25″ X 9

Vehicle Weights

  • Naturally Aspirated 4-cylinder minimum weight. 1800lbs max displacement 2.8L
  • Nitrous Power addition 4-cylinder minimum weight 2000lbs


  • 4-cylinder FWD Manual or Auto 67.9 mm single (102.36mm max compressor cast or billet exducer) Nitrous ok 2300 lbs.
4-cylinder FWD Manual or Auto 72.9 mm single (106mm max compressor cast exducer) (102.36mm max compressor billet exducer) Nitrous ok 2400 lbs.

* Turbocharged cars with cast inducer wheel: deduct 100 lbs.

* Nitrous power adder only: deduct 400lbs

* SOHC cars: deduct 400 lbs.

* Naturally Aspirated Cars with a maximum displacement of 2.6L: deduct 500lbs.

* Air to Water Intercooler: add 100lbs