Pro 4 Rules

 

1.      Body: Sedan and pick-ups only. Body does not have to remain stock but must be stock appearing. All cars must be completely and neatly painted. A 12-inch tall number of contrasting color must appear on both sides and on the roof of the car facing the outside of the track. A 6-inch tall x 1-inch wide white number must be located on the upper right hand corner of the windshield. Aluminum fenders, doors and hoods are allowed. Aftermarket nosepieces are allowed. A 4-inch tall spoiler on the rear is allowed and must be mounted on the trunk lid. Wings are not allowed. The body must remain at least four (4) inches off of the ground. Interiors must be stripped. All doors must be welded, chained or bolted shut. All glass except for the windshield must be removed, a Lexan windshield is recommended. Three (3) 3/8-inch diameter solid steel struts must be mounted directly in front of the driver, this is mandatory.

 

2.      Battery: Only one (1) battery is allowed. The battery must be securely located outside of the driver’s compartment. A battery disconnect is recommended and must be in easy reach of the driver and track officials.

 

3.      Brakes: Factory Stock four (4) wheel hydraulic brakes, all in good working condition.

 

4.      Bumpers: Stock appearing and in stock location. Reinforcement must be hidden behind the bumper. Bumper ends must be rounded of on the corners, no sharp edges.

 

5.      Coolant: Water is the only coolant allowed.

 

6.      Engine: Must be located in the stock location, solid mounts are allowed. Fuel injected, turbo charged, rotary or marine engines are not allowed. Headers are allowed. Roller camshafts are not allowed. Any hydraulic or mechanical cam is allowed. Compression ratio not to exceed 11.5 to 1. Any 500 cfm carburetor is allowed or a Holley 4412 un-altered except for the removal of the choke shaft and butterfly is allowed. A maximum two (2) inch thick adaptor plate is allowed. Aftermarket Aluminum heads are not allowed. Porting of the head is allowed. Any battery operated ignition system is allowed. Factory stock intakes only. Power pulleys and adjustable cam sprockets are allowed. Aftermarket pistons and connection rods are allowed. Open-air cleaners 4-inch tall x 14-inch diameter maximum are allowed. Maximum 2.5 liter

 

7.      Drive Axles: Can be welded, posi-traction or limited slip.

 

8.      Drive Shaft: Made of steel only. Must be painted white and have front and rear hoops made of steel to prevent the drive shaft from coming off of the car.

 

9.      Fire Extinguisher: All cars must be equipped with a working, securely mounted ABC type extinguisher within easy reach of the driver or track officials. Minimum of 3 lb.

10. Fire Suits: Mandatory and in good/safe working condition.

 

11. Fuel: Pump gas only

12. Fuel System: All cars must have a fuel cell securely mounted in the trunk. A firewall must separate the trunk from the drivers compartment. Fuel lines cannot pass through the drivers compartment. Electric fuel pumps are not allowed. Minimum of 8-inches of ground clearance.

 

13. Helmet: Mandatory. Must be Snell 95 approved and in good/safe condition.

 

14. Mirrors: Not Allowed.

 

15. Mufflers: Mandatory. A 2 ½ diameter exhaust pipe must exit from under the car behind the driver. Maximum allowable noise level is 100-decibel.

 

16. Neck Brace: Mandatory during all events. Must be approved for racing purposes.

 

17. Radiator: Any radiator is allowed. The radiator must be mounted in the stock location. Any reinforcement to protect the radiator will be mounted behind the grill. A one (1) gallon catch-can must be mounted on the firewall in the engine compartment.

 

18. Roll Cage: All cars must have a six (6) point roll cage system made of 1 ¾-inch diameter, .095 wall thickness tubing welded to the car frame. Three (3) drivers side sissy bars made of the same roll cage material are to securely mount to the roll cage to protect the driver during side impact. A steel plate 16 x 24 x 1/8 must be mounted to the sissy bars to protect the driver. If the car does not have a frame a 6 x 6 x 1/8 thick steel plate must be securely bolted to the body. The roll cage and sidebars must be securely welded to the plate. All bars around driver’s head must be padded with roll bar padding.

 

19. Seat: Aluminum racing seat is mandatory. The seat must be securely fastened to the body and roll cage.

 

20. Seat Belts: Mandatory. Five (5) point seat belt system is required. Quick release lap belt must be securely mounted to the roll cage or frame. The belts must be coded and dated. Five (5) year maximum age of the belts.

 

21. Shocks: Racing shocks are allowed. The shocks must be mounted in the stock locations.

 

22. Suspension: Must be mounted in the stock locations. Adjustable spring spacers and screw jacks are allowed. Struts made to be notched for camber and caster adjustment are allowed.

 

23. Tires: Hoosier Sportsman Racing Tires only. Allowable sizes are: 23.5/7/13 and 23/7/13 and 27/8/15 and 26.5/8/15 used in any combination.

 

24. Tow Hooks: Mandatory on the front and rear of the car. Must be made of chain that is at least 5/16-inch link size.

 

25. Transmission: Stock transmissions only. Made for racing clutches and flywheels are allowed.

 

26. Weight: Minimum weight of 2300 lbs. 55% maximum left side weight.  All added weight must be painted white and mounted with ½-inch bolts. In the interest of competition, Track Officials reserve the right to adjust weight as needed.

 

27. Wheels: Only Steel made for racing wheels are allowed. Maximum allowed width is 8 inches. Any mount of back spacing is allowed as long as the wheels and tires do not protrude past the body panels. Aluminum, Magnesium, home made and drilled wheels are not allowed.

 

28. Window Nets: Mandatory made for racing nets only. The nets must have a quick release mechanism securely mounted to the roll gage.