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2024 Rules Update: ALL Diesel Tractors with a 3.4 inlet turbo at 470 cubes MUST run a smooth bore turbo.

410 Diesels can run a map grove 3x4 turbo. In the 6,500 class you will pull at 6,700 pounds. In the 6,250 class will be able to pull at 6,400 pounds.



1. Cubic inch 

A. Diesel Engine-470 no Intercooler

B. Spark ignition on alcohol-370

C. Diesel - 410 Intercooler allowed

C. 315 cubic inch diesels are allowed two turbo chargers, with three (3) inch intake limit.

D. No V-8 engines permitted.

E. Intercoolers are not allowed for any vehicles, diesel or alcohol with the exception of the following: diesel 410 cu in or smaller may run an intercooler with a max turbo size of 3” with .250 map groove. 

2. A 1% tolerance will be given on cubic inch limitations to allow for normal engine wear. All engines are subject to be checked for cubic inch limits at any time. 

3. Cast iron OEM cylinder heads only, cylinder head must match block and valves must maintain factory angle. Lateral movement of valves only. Valves must seat in bottom of OEM Head, on all 6 cylinder engines. 

4. Only ONE plate permitted between the top of the block and the bottom of the cylinder head, with a maximum thickness of 1 1/8th inch. 

5. Cylinder heads are limited to two (2) valves per cylinder. 

6. Cylinder heads limited to (2) valves per cylinder. 

7. Rear of engine must be in stock location for make and model of rear end and transmission housing, maximum 1-inch adapter plate. Engine must be rigid to OEM transmission and rear end housing. 

8. Blanket minimum width of 17 inches. 

9. One (1) spark plug per cylinder. Alcohol Tractors: Single turbo charger of a size not to exceed a 3-inch diameter measured at the front face of the wheel with one single air inlet with no additional openings in compressor housing outside of the 3-inch inlet. Bushing must be permanent. Diesel Tractors: Single turbo charger not to exceed 3 inch in diameter at the ID of the bore or housing or bushing. All bushings must be permanent. Diesels are permitted MAF enhancement. No MAF enhancement on Alcohol, unless the engine is 310 cubic inches or less. 

Diesel Only: May run a turbo no larger than a 3.4 compressor wheel, Smooth bore with NO MAF enhancement. The compressor wheel must protrude into the housing 1/8th inch, and the compressor housing opening can be no larger than 3.4075 at the wheel. 1. No fuel injection pump larger than a 6 cylinder P-7100 series pump will be accepted. 

2. Water injection allowed with oil-lubricant only, no additives allowed in injection water. 

3. No super chargers allowed. 

4. Blow-by tube (oil or water) must come out in front of the rear tires or discharge into a puke tank. 


1. Maximum length 13 feet measured from center of rear axle to forward most point excluding tow hook. 

2. Any auxiliary transmission must be in factory housing. 

3. Maximum wheelbase 114 inches. 

4. OEM tractor rear end and transmission housing only will be accepted, no component tractors allowed. 

5. Hitch will be no SHORTER than 18-inches measured from the center of the rear axle to the hooking point. 

6. If drawbar has provisions to be made SHORTER than the legal length (18 inches from the center of the rear axle) is not acceptable as a legal drawbar. (NTPA rule book pg.19) 

7. Maximum hitch height 20-inches. 

8. Engine, bell housing or torque tube must be rigid to rear-end housing with OEM cast iron. Cast iron must maintain its form and not crack or break. 

9. Tractors with tub style stock chassis (Oliver, White, etc.) must keep the tub mounted from rear of the engine or engine adaptor plate to the rear end housing bolted in the stock location. The engine CAN NOT move independent from the rear end housing. 

10. Tubs can be modified and lightened but must maintain its OEM form. 

11. Tie bars or full frame is mandatory and must support the weight of tractor. 

12. No type of front-end suspension permitted, swivel front axels are ok. 

13. No front end suspension allowed. 

Tires: Maximum tire size 30.5 x 32 


1. Acceptable fuels are diesel fuel, alcohol. 

2. No oxygen carriers or combustion accelerators will be permitted. 


1. All tractors must be equipped with a 6-buckle blanket, with a 4.1 SFI rating. NO EXCEPTIONS 

2. All tractors must has 2, 3/8 cross bolts in the exhaust pipe. 

3. Side panels, Fire Wall and Fenders are required on all tractors. 

4. Fender must be constructed so that when driver is secured in the competition position, no part of driver’s body can touch the tires. 

Weight: 6000 lb. 

Front Hitch - All vehicles must have a front hitch attached to the vehicle that is capable of supporting the weight of the front of the vehicle. It must be the furthest most point on the vehicle and be centrally located. The hitch must have a minimum of a 3 inch diameter hole to allow for the 3 point mounted hitches on the movers to manipulate the competing vehicles. No weights are to be positioned next to the hitch in a way that may restrict the turning radius of the movers once they have picked up the front of the vehicle. 

Chassis - Maximum of 114 inch wheelbase unless originally produced with a longer wheelbase at which point the wheelbase will remain stock. Maximum length of 13 feet from center of rear axle to forward-most point of vehicle excluding the front hitch. No component tractors allowed. Wide front ends only. Must be OEM tractor rear end and transmission. No Component chassis allowed. 

Drawbar - Must be a minimum of 18 inches behind center of rear axle, a maximum of 20 inches in height, and be ridged in all directions. Hitching eye to be a minimum of 1 inch thick with a 3 inch by 3.5 inch inside diameter hole. 

Floorboard - All vehicles must be equipped with a floorboard. Fenders - All tractors must have fenders and must support weight of driver. Top of fender must extend no less than a 6 inches over the top of the tires. 

Roll Cage - Tractors must be equipped with a roll cage with an SFI 5 point harness. 

6,250 Light Limited Super Stock

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