2013 SUPER STOCK FOUR CYLINDER NATIONALS RULES
BODY AND CHASSIS SPECS
1. Any stock appearing metal bodied four cylinder car or truck –1965 through the current year.
2. You may run an aftermarket fabricated body. The body must be made from magnetic steel or aluminum. The fabricated body, body mounting positions, and overall appearance must retain stock dimensions, original body lines and contours. Must be centered over the wheels. If you run an aftermarket Late Model style body, the car must be neat in appearance. No wedge shape or box style bodies. You may use Five Star or Performance Bodies replacement panels. No MD3 type components.
3. Must have the make of car, the required weight, and C.C. on the hood or front fenders.
4. You may use an aftermarket nosepiece and rear bumper cover. Must match make of car, if applicable. No fabricated front bumpers. No open rear ends. May use a minimum 18” solid filler panel, in lieu of the rear bumper cover.
5. Boxed-in interiors permitted, but must have a removable inspection panel on the right side. The interior must be strong enough to support the weight of emergency personnel, if necessary.
6. All cars must have a minimum ½” at the top of the front fenders, doors, and rear quarter panels. No sharp edges.
7. No wheel flares to extend beyond 2” of the outer wheel.
8. The minimum ground clearance will be 4” at any point of the body. Skirting is allowed, maximum 6 inches.
9. The rear quarter panels must not exceed 66” in width at any point as measured at the top of the panel. The maximum height from the ground to the top of the rear deck and quarter panel will be 38”. No point of the body may be wider than 74”.
10. Only aluminum or lexan-type rear spoiler will be permitted. The maximum overall height of the rear spoiler will be 6”. Rear spoiler and braces mustmeet templates. (6” of surface material plus the bends, the top of spoiler may not be bent upward). The maximum width of the rear spoiler will be 62”. The spoiler must be attached solidly to the deck, no raised spoilers or wings. Maximum 3 braces or supports may be used, must meet template.
11. The roof must be stock appearing and mounted level to the body and centered on the body, as viewed from the front or rear. The minimum height of the roof must be 48”. A maximum 1 ½” bend or roll, turned downward, will be permitted along the front edge of the roof. A maximum 1” bend or roll, turned downward, will be permitted along the rear edge of the roof. Any other modifications to the roof will not be permitted. The roof post and spoiler supports may not overlap. All roof side panels and supports must extend to the edge of the body. The left and right side window sail panels must match, 18” maximum at the top and 36” maximum at the bottom.
12. Entire floor pan and fire walls must be un-altered.The front firewall must have all openings covered in case of fire or fluid leak in the engine compartment. The front roof supports / door jambs must remain intact a minimum of 18” above the chassis rail / rocker panel and they must be braced from the chassis. An extra foot brace may be required, if necessary. The rear firewall must be covered with sheet metal or aluminum to separate the driver’s compartment from the fuel cell area. If the firewalls are altered or the front roof supports/door jambs are altered, weight penalties will be assessed up to 25 pounds per side for infraction of this rule.This weight must be welded or bolted properly at the location of the infraction. (part of total weight)
13. The front, main, and rear chassis rails must remain in the car and un-altered. If the stock chassis rails are modified or altered in any way, there will be a weight penalty for infraction of this rule.You may tie the uni-body chassis together. Absolutely no bracing under the car. If damaged, the front chassis rails may be replaced with tubing in front of the cross member. The sway bar may be connected to this tubing, but no other suspension components. If damaged, the rear chassis rails may be replaced with tubing behind the rear end housing. No solid tubing front to rear.
14. All cars must maintain the stock wheelbase. Rear wheel drive cars only.
15. Windshield is optional, if removed, you must have five protective bars on the driver’s side. They must be between 4” and 5” intervals. They must be magnetic steel. No front side door windows allowed. You may fill in rear side openings, if applicable.
16. All cars 2000 C.C. and under – 2000 pounds minimum. Over 2000 C.C. – 2300 pounds with the driver after the race.
17. The engine maximum is 2500 C.C.
18. Engine must be in the stock location, this means factory height and setback. You may run solid motor mounts, but they must be stock size.
19. Zero decking allowed on the block, it must be a factory production steel block. All components of the engine must be stock production for the manufacturer of the block. Cylinder head and block must match factory production.
20. Any oil pan. May relocate the oil filter. No oil cooler allowed.
21. Must be a stock stroke crankshaft. Can use any rods. Crankshaft and rods may be stock or aftermarket.
22. Any flat top pistons. Toyota 3TC may run a dome of .235” maximum. Toyota 20R/22R may run a dome of .127” maximum.
23. Any clutch and flywheel permitted.
24. Stock production head and intake. No porting, polishing, or acid washing of the runners. Bowl blend allowed. No spacer between the head and the intake. No factory dual plug heads. One spark plug and two valves per cylinder maximum. No aluminum head on Fords.
25. Head of the valve must be stock diameter. May cut the spring pocket. Double valve springs permitted.
26. Cutting the lifter boss is permitted. Lash caps are permitted. May be hydraulic or solid lifters.
27. Aftermarket timing gear allowed to match cam key type. External adjuster permitted. No roller cam or rockers. Any lift on a flat tappet cam.
28. Holley 500 CFM (4412) or Holley 350 CFM (7448) must be used. No modification, except for choke housing. It must pass the track tool. Maximum 3” spacer. Adapter allowed to fit the Holleyto the intake.May cut intake to match adaptor bore sizes– No Polishing.
29. Mechanical or electric fuel pump permitted.
30. Must run a stock distributor. May run an aftermarket ignition system. No magnetos and no dual point distributor. Must have an operable starter in working condition.
31. Headers permitted.
32. Transmission and differential must be stock manufactured OEM production. The transmission must have a minimum two forward gears and one reverse, plus neutral position. You may weld the rear end gears or run a spool, but no other aftermarket devices. May run an adjuster and right front shut-off.
33. All cars must have an approved scatter shield and / or approved bell housing.
34. All suspension components must remain stock in their OEM mounting locations for the year make and model of the vehicle, unless otherwise stated.
35. The steering shaft may be a collapsible shaft. Aftermarket steering wheel and quick release are permitted.
36. Must use stock type magnetic steel shocks bolted in the stock location. No adjustable shocks. No coil spring attached to the shocks. Ford Pinto may relocate the front shocks for wedge bolt assembly. Toyota may run adjuster on stock front strut.
37. Springs must be located in the original position. You may run aftermarket springs, but you may not modify the spring bucket in any way.
38. May run screw jacks, wedge bolts, or adjuster cups.
39. Shackles permitted on the rear springs. Lowering blocks permitted. Stock type OEM multi-leaf style springs must be magnetic steel.
40. Strut cars must run stock or OEM replacement components, may brace top of tower. May alter the top of the strut tower with a slotted plate for the purpose of setting caster and camber. The strut towers must remain intact for support. If the strut towers are removed, you must add 35 pounds to the frame rail or chassis rail on each side that is missing. This weight must be welded or properly bolted in-line with the struts. (part of total weight)
41. Stock front and rear sway bars only, no adding of additional devises. No other adjusters allowed.
42. Any steel wheel 8”- 10” wide X 13” maximum. Bead lock rims permitted. Safety beads required on all wheels. One inch lug nuts recommended.
43. Racing fuel or pump gas only. No alcohol or additives.
44. Cars will be inspected for tech and safety items prior to competition. Track official has the final approval. Safety rules can be found in the 2013 General Rules section.
45. All other provisions will be dealt with through weight penalties, at tracks discretion.
46. Any tires. Any compound.
For any tech related questions, please call Four Cylinder National Tech Inspector, Garry Wilson at 919-614-1703.