ENGINES (HOT STOCK, OPEN STOCK, SUPER STOCK, PRO STOCK)
  1. Original HP limited to class being entered.
  2. Hot Stock stroke, however bore may be a max of .050 oversize, .005 max
    wear allowed.
  3. Must be a lawnmower or lawn tractor engine (factory design)
  4. Any type of oil pump allowed.
  5. No pressed steel cranking pulleys allowed.
  6. Must have an engine kill switch at rear of tractor within 6" of center.
  7. Exhaust must be directed upwards away from track.
  8. Must be naturally aspirated and must use a factory type carburetor.
  9. Must use original engine manufacturers carburetor, recast allowed.
  10. Overhead valve engines may be run in any class.
  11. Overhead valve engines will not be considered legal if the same engine,
    relative to design and displacement, is labeled by the manufacturer at a
    higher HP than the class being entered.
  12. In Kohler engines where the cylinder casting is common to several HP's, it
    may be bored or sleeved to meet bore for class being entered,
ENGINE ENCLOSURE
  1. Tractor must have hood and grill, or safety plates in a manner so as to prevent
    parts from a blown engine, flywheel, clutch, or drive train from going into
    spectators.
  2. Wire blanket shields are permitted.
  3. Steel shields around clutch and flywheel of 1/8" steel or 3/16" aluminum are
    required.
  4. Owner/operator is responsible in case of accident.
  5. Stock flywheel cover plus engine compartment side covers qualify.
FRAME/AXLE (EXCEPT MODIFIED)
  1. Frames must be stock length and wheelbase.
  2. Axle must be a lawnmower or lawn tractor trans axle.
  3. 10 HP stock class must be "V" belt driven, idler pulley as clutch.
HITCH
  1. Hitch height not to exceed 13" from ground to top of hook point.
  2. Hitch must be rigid in all directions.
  3. Hitch must have 1 1/2" hole and be at least 1/2" thick, but not more than 3/4"
    thick at hook point.
STABILIZER/WHEELIE BARS
  1. Stabilizer bars must be rigid in all directions.
  2. Wheelie bar contact point must not be more than 5" from ground.
  3. Contact point must be at least 18" from center of rear axle.
WEIGHTS
  1. Weight bars must not exceed width of tractor.
  2. All weights must be securely fastened.
THROTTLE
  1. All tractors must be equipped with a deadman throttle (spring loaded).
NON-MEMBER TRACTORS
  1. Non-member tractors must be inspected prior to pulling to insure all safety
    rules are met.
  2. The inspector (a member of the Protest committee) must be allowed to look
    at engine shields, drive shaft area, clutch shields. kill switch, wheelie bars, tire
    size, weight bars, weights, hitch location, and question fuel type.
  3. All competing tractors are subject to protest.
STOCK ALTERED - NQS RULES
  1. Single cylinder four cycle flathead engines only.
  2. Stock head bolt pattern=>stock head gasket must fit over studs or bolts.
  3. Stock head bolt location and bead bolt size.
  4. Maximum crankshaft stroke 3.25"
  5. Maximum engine bore 3.780"
  6. 36.5000 cubic inch limit (no tolerance)
  7. Maximum engine valve size 1.380"
  8. Maximum engine valve lift .330".
  9. Maximum carb venuri size 1.00", no air entering after 1.00" restriction, venturi
    must be round in shape.
  10. Carburetor must be mounted to the engine with no more than 1" spacer.
  11. No reverse port engines allowed, carburetor must go to the original intake port.
  12. Carburetor must be a stock appearing Kohler-type.
  13. Billet heads permitted.
  14. Porting and polishing allowed.
  15. No external welding or external modification allowed.
  16. All thread through finned area is acceptable.
  17. Welding permitted in crankcase area of the block for repair.
  18. Methanol only, (NO NITRO OR ANY OTHER FUEL ADDITIVE)
  19. Must run a factory appearing hood and grill.
  20. 1Tractors must have garden tractor rear-ends.
  21. Tractors must use stock garden tractor frames.
  22. Frames must maintain factory length.
  23. Weight class 1050 lbs (both rounds)
  24. Wheelbase: 52 inches maximum.
  25. Top placing tractors will be checked for, but not limited to: Fuel, Bore, Stroke,
    Carb Size, Valve lift, Valve Size and Deck height.  Formula for CU,IN. is
    Measured Bore X Measured Bore X Measured Stroke X .785 Cu In.  All
    bores measured 90 degrees from thrust side.
  • Stroke: 3.250" maximum 0.010" measuring tolerance, must not exceed Cu.In.
    Limit,
  • Bore 3.780" maximum 0.010" measuring tolerance, must not exceed Cu. In.
    Limit.
  • Carb: 1.000" venturi size maximum 0.001" measuring tolerance.
  • Valve Size: 1.380" maximum 0.001" measuring tolerance.
  • Head Bolt Pattern: Stock Gasket must fit over head studs or bolts.
NOTE:  If you have the factory fan shrouding in place and during tear down the tech
person needs to inspect your engine's intake port, you will be required to remove
the shrouding, even if it requires removing the engine from the chassis.  So please
have your intake port visible for the tear down procedure.

RULE CLARIFICATION; what can and cannot be done to the outside of the engine
in the port area.  Any intake port will be checked including one's that have been
braced or repaired.  They will be checked for stock carb mounting and locations,
center to center distance, height and port location.  Excessive and unnecessary
build-up on the outside of the intake port will result in disqualification.  Build up is
port epoxy.  Weld or bracing or any other means of distorting the port's factory
dimensions.
TRACTOR SETUP
PIEDMONT LAWN AND GARDEN
TRACTOR PULLING ASSOCIATION
PGTPA