2025 Rules Update: Component Chassis WILL be allowed. PPL Rules will be followed.
 

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All OEM chassis Pro Stock rules, including shielding, safety and SFI requirements, apply to this class plus the following rules. 

Class weight: 8700 lbs. 

A. Engines: 

1. No engine larger than 540 cid. (+ or - 1 percent) 

2. No component chassis 

3. Engine head must be OEM agricultural-type for that brand engine. (No billet) 

4. No overhead cams allowed. 

5. Maximum 2 valves per cylinder 

6. No inner / after coolers 

7. Diesel fuel only 

8. Maximum allowed "P" pump 3000 or 7100 series only (No aftermarket housing). Only one plunger per cylinder allowed. 

9. All air will exit through a 4.5” opening of exhaust housing. Exhaust wheel must protrude 1/8th inch inside bore. Maximum inlet 5.0”