4500 LB. SMALL BLOCK 4X4 TRUCK RULES - 2021 - 2023

1. Body/chassis
   • Maximum wheelbase of 135".
   • vehicles must have closed doors, unless equipped from factory with fabric top.
   • Half cabs must have closed doors.
   • Vehicle must have stock appearing hood and front fenders.
   • Beds and rear fenders are required.
   • Engine compartment must be close to factory specifications or engine side shields are required. Rear of engine block can be no far further than the center of the front rear and engine must be behind the factory grill location.
   • No weights can extend forward more than 60" from center of front axle. All weight frames and weights must be stationary and safely secured to the vehicle.
   • Hood scoops-allowed.
   • Fuel tank must be located outside of cab.
   • working front brakes are mandatory.
   • Tire stagger - no more than 1/2 width of tire - front to rear. 
2. Transmission and drive lines.
   • Clutch/manual transmissions must have a SEMA approved bellhousing.
   • All universal joints covered with 6" wide, 5/16" steel or 3/8" aluminum.
   • All driver shafts must have a midpoint safety loop.
   • Torque converters and automatic transmissions must be equipped with an SFI approved safety shield or blanket. Automatic transmissions must have a flywheel. Safety shield and a positive reverse gear lockout. Standard transmissions must have a neutral safety start switch.
3.  Engine.
   • One four barrel, naturally aspirated (4150 or 4500 style) carburetor allowed. No Preditor or exotic carburetors allowed. Gas or alcohol only allowed. All forms of nitro-methane, including nitrous oxide and propylene oxide are illegal.
   • No fuel injection, blowers, turbo chargers, or nitrous oxide allowed.
   • Small block engine - 415 cubic inch limit Finished bore size and stroke are used to determine cubic inch. no aluminum blocks. Aluminum heads of any make with a valve angle no less than 9.5 degrees are allowed. The following aluminum are not allowed, SB2 ,R07 ,LS Chevy, Ford modular engine heads, and Dodge/Chrysler style Hemi. Anything new as of 2020 needs to be approved. Cylinder heads must accomodate a cast aluminum intake manifold, no sheet metal intakes allowed.
     
   • Pulling vehicles must be equipped with a deadman throttle. Throttles working in a forward-backward direction shall be closed in the rear most position. No hydraulic throttle linkage allowed. Linkage must be positive two way mechanical linkage.
   • A bolt in the crankshaft is required to hold the dampener pulley. Pulley to be shielded 360 degrees - SFI dampers exempted from shielding.
   • Engine fans must be completely shrouded with steel 1/16" or thicker - electric fans excluded.
   • The formula for calculating the cu. in. displacement of any piston engine is: Bore x Bore x Stroke x 7854 x Number of cylinders. The finished bore size of cylinder and stroke is what is used to determines cubic inch
     
   • All exhaust systers must discharge vertically - vertically is defined as being within 10 degrees (any direction) of "being plumb".
   • Height shall be a minimum of 12" above the bend in the pipe which discharges vertically, measured from the top of the pipe to the bottom of the bend.
   • Exhaust pipes must be securely attached.
   • Rain caps and megaphone pipes not permitted.
   • Venturi-headers acceptable.
4. Kill switch.
   • For spark ignition engines the kill switch must break or ground the ignition. circuit and must break electric power to an electric fuel pump(s) if so equipped.
   • Kill switch must have a minimum 2" diameter solid ring, with minimum 1/8" cross section thickness, attached to it. The cable from the sled must be able to be attached to this ring.
   • Kill switch must be mounted independently of drawbar and/or wheelie bars.
   • Location of kill switch, in rear center of vehicle, 24" above and within 6" off center of point of hook.
5. Hitch.
   • Hitch must be rigid in all directions, and parallel to the ground.
   • Minimum hitch length is 36" from center of the rear axle. Measurement taken from center of axle tube to hook point.
   • Hitch point to be a 3" wide & 3.75" long, 1" thick at any point. Hitch must be horizontal - not vertical.
   • Hitch pivot or attachment point cannot be any further forward than the center of the rear axle.
   • Hitch height to be 20" above the ground.
6. Tires.
   • Tire size limit of 31" x 15.5" x 15"
   • Barred tires allowed.
7. Safety.
   • Floor & firewall area must be completely covered with metal. No holes larger than 1 inch. 
   • Driver must wear shirt, shoes, and long pants.
   • Helmets and fire suits are required.

    Note: All pullers must be registered 30 minutes before pull starts.