1. Factory three cylinder liquid or air cooled diesels. (No cut down 4 cylinder engines)
2. 75 cubic inch limit.
3. Water injection permitted, water or water soluable oil mixture only.
4. Stock head for engine make and model, no external welding except for repair.
5. No overhead cam engine.
6. Stock OEM intake and exhaust manifold. Porting and polishing allowed- no tube manifold.
7. Engine block model and serial numbers must be visible.
8. Stock or component frame with stock appearing garden, compact, or farm tractor sheet metal with full engine shields. Tube chassis must be covered with sheet metal.
9. No billet fuel injector pumps or electronic fuel injection.
10. Limited to one (1) turbo, no size restriction.
11. No intercoolers or ice boxes allowed.
12. Kill switch must shut off electric fuel pump and shut air off on compressor side of turbo.
13. Exhaust "L" of turbo must have minimum of 5/16 inch cross in elbow with exhaust to discharge vertically.
14. No propane or nitrous of any kind.
15. Must run 1/4 inch cable around oil pan, over top of valve cover, in between #1 and #2 cylinder, in a complete circle, connected with cable clamps, minimum 2 clamps.
16. Steel flywheel required with flywheel inspection hole in bellhousing.
17. Flywheel, front cast pulleys and clutch must be shielded 360 degrees with 1/8 inch steel or 3/16 inch aluminum. SFI approved scatter blanket also accepted.
18. No belt driven cooling fans allowed, must be electric fan.
19. Rules may be revised at any time, without notice.
20. All other general and safety rules apply.
