Northwest Limited Modified 4x4 Truck
1. Weight – 6500 lbs
2. Engine – Open factory engine same as manufacturer of the truck. Cast iron block. Cast iron or aluminum heads. Electric fan and electrical water pump optional. Engine shielding same as Super Stock Trucks. Engine location, rear of block 12” from center of front axle plus or minus 1”.
a. Gas engines limited to 540 cubic inches.
b. Alcohol engines limited to 430 cubic inches.
3. Headers – Open headers. Exhaust must exit below the truck with deflection shields or turn downs or vertically through the hood.
4. Intake – Cast aluminum intakes allowed. No tunnel rams or sheet metal intakes. One (1) complete single four (4) barrel carburetor only.
5. Drive Shaft Safety Requirements – Same as Super Stock. All trucks must have three (3) round metal loops shielding in each drive shaft two (2) piece drive shaft will have six (6) metal loops). 360 degree loop must be a minimum of 3/8” thick aluminum, or ¼” steel, ¾” wide (or wider) and not more than two (2) inches from the shaft in any direction. End loops to be placed no further than six (6) inches from universal joints, with third loop in center of shaft, or can be a solid tube (3/8” aluminum or ¼” steel) meeting the above requirements. No cast metal. All trucks will have a 360 degree metal shield around the universal joints, 3/8” thick aluminum or ¼” thick steel, minimum width six (6) inches.
6. Kill Switch – Same as Super Stock. Switch must be located in the rear center of the truck (maximum six (6) inches off center in any direction), 24” above the point of hook.
7. Suspension – Solid suspension allowed. Traction bars optional, front and rear.
8. Wheelbase/Frame – The total length of the truck should not exceed 195” from the center of the rear axle to furthest point of the weight bar and the hitch should be no shorter than 33” long from center of rear axle. Any OEM wheelbase and frame. No tube chassis (custom) permitted.
9. Tires – 35” x 12.50” maximum as stamped (or metric equivalent of 315/75). a. All tires must be DOT approved and carry factory stamping of DOT number on sidewall. b. No cuts, hot knife marks or modifications are permitted to tires. No dual wheels, chains, studs or stock car tires. c. No deflector shields front or rear behind the tires.
10. Weights – Front weights permitted. Maximum overall 195” from center of rear axle to furthest most point of weights. No moving front axle from OEM location.
11. Transmissions/Clutches – Single OEM equipped transmissions and transfer case of a one (1) ton blow proof bell housing or blanket. All competitors may be required at registration, to sign a transmission and clutch certificate waiver stating the competition vehicle meets all safety requirements.
12. Safety – Fire jacket & helmets required.
13. Hitch – Full 3.5” minimum I.D. loop required. 26” maximum height. From point of hook to centerline of rear axle shall be no less than 27% of truck wheelbase but no shorter than 33". Drawbar angle cannot exceed 33 degrees (Tech inspector has discretion). Must be stationary in all directions. Hitch must be accessible.
14. Fuel – Gasoline only for 540 cubic inch engines, Gasoline or alcohol for engines 430 cubic inch or less. No oxygen accelerators.
15. Fuel Tanks – All fuel tanks must be located in an open area or in weight box. Fuel tanks may not be located under hood or in cab, unless factory installed tanks are used. However, factory installed fuel tanks may be moved to an open area. Must have a manual shut-off at the tank.
16. Electric fuel pump optional, but must be hooked up to the kill switch.
17. Hood modifications for air cleaner/header exits. Body must be steel and panels in place. Must have firewall, bench seat or one bucket seat, switches optional. Wood and fiberglass bed are permitted. Any floor or tonneau cover permitted. Driveline must not be visible.
18. Must have working brakes on front. Lights and rear brakes optional.
19. Door has to work. Glass, plexiglass or lexan allowed. No tinted windows.
20. Fire extinguisher in cab is required. Helmets and seatbelts required.
21. No planetary rear-ends.
22. No electronic traction control devices of any kind permitted.
23. All trucks will be tech inspected before they can pull and engine must pumped and approved before any winnings being paid out. Pumping must be done at that event if engine does not already have approved engine seal. They will have to provide two (2) intake bolts with holes of 1/16” to be sealed or other club official approved method.
24. Rules will be reviewed every two years.
25. No Northwest Limited Modified 4x4 truck is eligible to pull Northwest Performance Street. However, you can pull with Northwest Super Stock, but you must comply with all Northwest Super Stock safety rules.
26. Any driver arguing with a track official is subject to immediate disqualification. All decisions of the track official will be final at each pull. Any protests will be settled at next club meeting.
27. All rules to be interpreted by officials. Any unforeseen problems or oversights will be ruled on by officials on sight. All general and safety rules apply. All rulings will be final. Officials reserve the right to allow or disallow a competition vehicle to compete on the basis of any safety concern or infraction.
Rules changed and approved 11/14/14. Changes in red
Rules changed and approved 1/10/17. Changes in blue.