Limited Modified Tractors are those using engine(s) up to a maximum capacity of 375 cubic inch. The engine may employ a roller camshaft and be naturally Aspirated, with a maximum of 1 venturi per cylinder (ie. dual 4 barrel carburettors are allowed), no blowers or turbo charging. All engines are limited to two valves, one spark plug per cylinder. All LS series engines must use OEM cylinder heads and thermoplastic inlet manifolds with either one of the following casting numbers showing.
#12590123, #88958675, #12573572, #12590124, #88894339, #12589181, #12602477, #12560894
Must use factory electronic fuel injection and fuel injection system and fuel injector.

Weight classes are:

2500 kg
2900 kg
3400 kg, excluding driver

No portion of a limited modified tractor may exceed 14 feet forward of the centre of the rear wheel, including removable ballast. Maximum width of vehicle is to be 8 feet at its widest point including ballast.

Legal fuels are restricted to pump fuels (Unleaded Petrol (ULP), Premium ULP and Aviation Fuel (AV Gas) is allowed and no additives may be added thereafter).