1. All OEM chassis NTPA Pro Stock rules, including shielding, safety and SFI requirements, apply to this class plus the following rules.
1. No engine larger than 540 cid. (+ or -1 percent)
2. No component chassis.
3. Engine head must be OEM agriculture-type for that brand engine. (No billet)
4. No overhead cams allowed.
5. Maximum 2 valves per cylinder.
6. No inner or 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. Any size turbo may be used.