8500 Limited Pro Stock Tractor Rules

  1. 474 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 3.0 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 4.0 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 3.0 opening in compressor or 4.0 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.
  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 ¼ 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. Pro Field tractor’s will be allowed to use a removable slug to fit the turbo requirements of the 8500 Pro Stock class if, and only if, they are running a box gt 42 turbo. The removable slug must be held securely in place by a set screw or other method, and must completely close off the openings for the MAP grooves. If at any point the pro field class changes their rules to run anything other than the box gt 42 turbo, they will be required to meet the turbo rules for the 8,500 Pro stock class if they wish to jump into the class. No EXCEPTIONS. Any pro field tractor wishing to pull in the 8500 Pro Stock class with the removable slug will be required at each pull to contact one 8500 Pro Stock driver entered in the class at that event, and ask them to verify that the slug is in place before they hook to the sled. Failure to prove the slug is in place (verifying with a 8500 Pro Stock driver), and or hooking in the 8500 Pro Stock class without the slug in place will result in the following consequences:
    1. First offense is forfeiture of prize money and all points (max of 16) for that class.
    2. Second offense is forfeiture of prize money for that class, and all points accumulated for the year to date in the class.
    3. Third offense is 1 year and 1 day suspension for that tractor and primary driver for all classes in which it competes. If there is not a single 8,500 Pro Stock tractor at an event, the Pro Field tractors may pull in the 8,500 Pro Stock class without the slug in place.
  16. Rules locked for 3 years (2013 through the end of the 2015 season).