9,500 Limited Pro-Stock Tractor Rules

  1. 650 cubic inch limit.
  2. Kill switches are mandatory and must be easily reached by driver while sitting. Air shutoff must be spring-loaded closed.
  3. The turbo compressor inlet diameter to be measured at the face of the wheel, a maximum of 4.1 inches. Tips of the wheel must protrude into opening at least a 1/8 of an inch. Housing may use a reducer or slug if welded in place, no setscrews or provisions to remove slug. Tips of wheel must still protrude into opening.
  4. The turbo exhaust outlet diameter to be measured at the face of the wheel, a maximum of 4.7 inches. Tips of the wheel must protrude into opening at least a 1/8 of an inch. Housing may use a reducer or slug if welded in place, no setscrews or provisions to remove slug. Tips of wheel must still protrude into opening.
  5. No functional waste gates. No air entry after the 4.0 opening in compressor or 4.7 opening in exhaust housing. No MAP width enhancement groves or air entry of any kind. No variable geometry turbos.
  6. Waste gated exhaust housing allowed, but must be altered to look like non-waste gated exhaust housing. All passages internal and external must be plugged.
  7. One Bosch type injector pump, no sigma style pumps. Limited to P7100 with a 13mm barrel and plunger except for 4.1.
  8. No nitrous oxide or propane.
  9. Tire size maximum of 24.5x32.
  10. Tractor must have side shields covering engine compartment that will contain any fluids or engine parts.
  11. Tractor must have steel flywheel, no cast iron allowed.
  12. Tractors will be equipped with a clutch blanket or steel shield no less than inch thick and 5 inches wide.
  13. Engine must run on factory designed fuel.
  14. 2 springs to pull throttle back to idle; 1 on pump 1 on throttle handle.
  15. Allow 9500 Pro-Field tractors weighing 9500 lbs. with an an 18 inch drawbar and 2800 RPM's to step up to 9,500 Limited Pro-Stock Class. Allow 11,000 Hot Stock Tractors can drop to the 9,500 Limited Pro-Stock Class weighing 9,500 lbs. and running the 11,000 Hot Stock rules. Board will review and modify if needed.