- Tractors must be or 1953 or older
- Tractors should be restored to as near original as possible with original fuel tank, hood and radiator in place as intended by the manufacturer.
- Belt driven fans must be shrouded in .125″ steel 360 degrees.
- Electric driven fans and water pumps are allowed.
- Standard tread tractors must be equipped with original appearing wide front end and original appearing fenders, replacement fenders allowed with the approval the IPA board.
- No alterations may be made to tractor chassis other than pressed wheels, belt pulley, P.T.O., hydraulic covers, transmission and differential covers which may be made from steel or sheet metal (no magnesium, wood, etc.; replacement parts).
- Tip over bars and weight brackets may be aluminum.
- Engine side shields will be allowed.
- Engine must conform to chassis being entered.
- Tractor may have O.E.M. 2wd agricultural replacement block, cylinder head(s) and crankcase with the same number of cylinders intended by the manufacturer for make and model of tractor.
- Block and cylinder heads must run fuel as originally intended by the manufacturer.
- No spacer or shims more than .455 of an inch total in the area from center of the crankshaft to top of head (this measurement includes all gaskets).
- Any Cast or Manufactured cylinder head will be accepted. Cylinder head must retain OEM width and length for the engine application. Valves must retain OEM angle for engine application. Cylinder head must retain OEM bolt pastern for exhaust manifold and intake manifold. Cylinder heads are limited to 2wd agricultural replacement for make of tractor being entered. Must bolt on without any modifications.
- Any amount of material may be removed from the OEM casting.
- Material may be added to the OEM casting only for normal repairs and to redirect coolant flow. No material may be added to allow for increased air flow, increased valve size or to reshape combustion chamber.
- Any size valve, valve seat and valve guide may be used.
- Each competing vehicle must have a working RPM pick up on their vehicle. The pick up must be wired uninterrupted to a common 3 prong household electrical receptacle that is to be mounted on the back of the vehicle directly above the drawbar area. The pick up MUST be in working order during competition. If a competitor’s pick up does not work at an event, a competitor may be hand tached immediately after leaving the track after a competitive pass. A competitor must be tached trackside. If a competing vehicle leaves the track area before being tached, the vehicle will be disqualified. Engine speed over 10% over standard RPM will be grounds for disqualification.
- The use of an auxiliary fuel pump is allowed.
- The use of an auxiliary fuel tank mounted outside of original fuel tank is allowed.
- Any fuel mixtures or pressure tanks are not allowed. LP will be allowed.
- No alcohol, nitro, nitrous oxide, octane boosters, any oxygen carriers or combustion accelerators of any type
- Tractor must be operated with a hand throttle as comes from the factory with no alteration or modification to linkage.
- No weight or weight frame may extend more than 11′ forward of the center of rear axle.
- Carburetor must bolt on to intake manifold with no modifications or adapter plates.
- Intake and exhaust manifolds must be cast with no external modifications. Must bolt onto cylinder head as intended by manufacturer. No adapter plates allowed.
- No visible modifications to any of the above items.
- Engine RPMs will be adjusted as per factory location.
- Air breathers do not have to be used. If air breather is used any variance must be approved by the IPA board.
- No artificial cooling of air or fuel.
- Tractor must run OEM type ignition system that it came with from the factory, may be updated to stock appearing mag, no external coil.
- Replacing points and condenser with electronic ignition allowed. MSD allowed.
- Tires are limited to a maximum 15.5-38. No radials
- Aluminum rims will be allowed.
- No Minneapolis Moline 800 engine parts allowed.