Maximum single 475 cubic inch no tolerance V8 engine.
Cylinder heads: two valves and one spark plug per cylinder. Aluminum heads are allowed.
Legal aluminum heads: CHEVROLET: Dart-320, 360, and Pro 1, Brodix 1 &2, and all Edelbrock. FORD: Cobra jet, Blue Thunder and TFS A460. CHRYSLER: Indy 444-1.
Not limited to these heads, but must meet A & B.
3a. Must have cast aluminum manifold.
3b. Must except stock rocker arm assembly.
The front of the engine block cannot extend more than 160 inches forward of the center of the rear axle or 20 inches forward of the center of the front axle.
Maximum height 30 inches.
Minimum 36 inches behind center of rear axle.
Maximum 48 inches behind center of rear axle.
Pivot point of the hitch can not be forward of the center of the rear axle.
Must be rigid at all hook points.
Must be no smaller than a 3½ inch hole at the hook point.
Tires & Wheels (2wd):
1a . Any uncut DOT tire.
No split rims; snap rings or dual wheels.
Transmissions & Drivelines (2wd & 4wd Pro):
Stock altered frames. No tube chassis.
Maximum wheel base 140 inches center to center.
All u-joints and yokes must have 360 degree cover, 6 to 10 inches long, and 125 inch thick steel wall(no exhaust pipe). Aluminum must be .250 inch thick & attached with grade 5- 3/8 bolts & a minimum of 2 required.
Solid drive shafts loops required. Must be fastened with at least 2 grade 5- 3/8 bolts.
Must have a fully enclosed S.F.I. approved explosion proof bell housing on standard transmission.
Must have S.F.I. approved flywheels for both automatic and standard transmissions.
Automatic transmissions must have S.F.I. approved flywheel shield and transmission blanket, or tunnel shield.
Any rear axle is allowed, but no planitaries.
Weights & Safety Rules (2wd & 4wd Pro):
Weights can be mounted anywhere on the truck in a safe manner. No loose weights in cab.
Weights cannot extend more than 60 inches forward of the center of the front axle, or any part of the truck.
Driver must wear seatbelt.
Batteries must be in protective case and must have a battery disconnect switch on outside if mounted in front.
Must be mounted and working fire extinguisher in the cab.
No gas tanks in the cab, unless factory installed.
Must have working kill switches and they will be checked.
Brakes must hold vehicle…steering brakes are allowed.
Must have radiator overflow.
Drivers must be at least 16 years of age and have a valid driver’s license.
No car bodies, vans, blazers, broncos, or fiberglass bodies allowed. With the exception of fiberglass hoods only.
Hood required covering as much area as possible.
Engine side shields required (.100 for steel and .125 for aluminum), unless inner fenders are installed.
Any single carburetor on gasoline, no other fuel.
No holes in firewall or floor larger than 1 inch.
Balancer must be S.F.I. approved or covered 360 degrees.
Nerf bars at least 8 inches behind clevis or body to prevent injury.
Fuels tanks are allowed to be in front of vehicle if they are S.F.I. approved and have braided hoses and pressure coupler.
2wd- must have wheely bars, maximum ground clearance of 6”, and 18’ behind rear end.