CLASS 4 (MRA)

Mudboy · CLASS 4 (MRA)

Addendum to Pro Stock frame rule:

Main frame rails can be constructed from a minimum of 2x3 rectangular tubing and must be a minimum of .080 wall thickness. No round tubing or ladder style frames allowed.

GENERAL
This class is for highly modified stock appearing four wheel drive race vehicles. Altered frames, race bodies and high performance race engines allowed.

BODY
1) Any style jeep or truck body allowed - must be recognizable - No excessive cutting of the body. Fenders and roof must be retained if originally equipped. No narrowing of body permitted.
2) Body must extend to and cover all front engine components
3) A firewall and floorpan must be present protecting driver from engine and driveline components. Minimum of 16 ga. Steel or .060 (.120 recommended) aluminum required. The firewall will extend from door to door and from the floor pan to the base of the windshield. The floor pan will extend from door to door and front of the cab or tub to to rear of the cab or tub. (NOTE the floor pan and firewall shall be securely attached to each other and to the frame work of the chassis).
4) Center seat acceptable, must be located no more then 84" from the center of the front axle to the bottom of the seat back.
5) Windshield not required.

DRIVETRAIN
1) Main frame rails can be constructed from a minimum of 2x3 rectangular tubing and must be a minimum of .080 wall thickness. No round tubing or ladder style frames allowed.
2) Minimum 8 point roll cage required
3) Any type suspension allowed
4) Any style OEM or aftermarket chain or gear drive transfer set ups allowed
5) Dual independent master cylinder brake system required
6) Four independent wheel brakes required
7) Maximum 46.5” unaltered DOT tires.

3000 lbs big block, 2700 lbs small block
9) Maximum wheelbase 130”

ENGINE
1) Any automotive type engine acceptable
2) Engine must be located with # 1 spark plug no more than 12” behind the center of the front axle tube
3) Big block aluminum engine blocks not permitted. Small block aluminum blocks are allowed.
4) Any type of cylinder head and intake manifold allowed
5) Maximum of 4 barrels of carburetion, with a maximum of (2) fuel bowls. (split and stretched Dominators allowed, single Predator only)
6) Vacuum pumps and dry sump allowed
7) No nitrous allowed

Racing gas or E85 fuel only(no methanol, ethanol or nitromethane allowed). No power fuel additives allowed.

Vehicles must meet all safety requirements.