A. Any American made push-rod type engine will be permitted as long as the rear of the engine bell housing flange is mounted at least 72”-inches forward from the center of the rear axle. The engine offset must remain within two (2”) inches of the centerline from the cross member. The minimum engine height when measured from the ground to the center of the crankshaft is 11” inches. Other engines of the push-rod type that meet this criteria may be approved for competition.
B. All engines used in competition must be able to be used in a conventional passenger car without alteration. Alteration of motor mounts will not be permitted. Alteration of the castings and/or fittings will not be permitted. Any machine work on the outside of the engine or machine work on the front or rear of the crankshaft will not be permitted.
C. Aluminum blocks will not be permitted with the exception of the CTC525 aluminum block.
D. Magnetos will not be permitted.
E. Wet sump oiling systems must be operative and will go with a claim by DIRTcar officials. Overall dry sump systems will not be permitted.
F. Alteration to the cooling system will be permitted. If alterations to the cooling system are made the stock-appearing hood line must be maintained.
G. The battery must be securely mounted and shielded. The battery must not be mounted inside the driver’s cockpit.
H. The exhaust system(s) must be mounted with the exhaust directed away from the vehicle and away from the ground. The exhaust system(s) must remain completely below the interior deck of the car. The entire exhaust system (including the exhaust pipe and/or header exits) must be inside all parts of the body. The only breach of any interior or exterior body panel that will be permitted is for routing the left side header or exhaust pipe on the left side of the car. When routing the left side header or exhaust pipe through the left side firewall a maximum of 1/2” inch clearance around the header or exhaust pipe will be permitted.
I. Local track rules will prevail when decibel and/or muffler rules.
J. One two or four-barrel carburetor is required.
K. The engine must be a normally aspirated configuration.
L. Fuel injection systems or electric fuel pumps will not be permitted.
M. There may be specific engine rules issued for each region of North America that deviate from the standard UMP Modified Engine rules included herein.