Vermont Tractor Pullers Association
Sport Stock 1050 lbs & 1150 lbs 2015-2018 Driver Eligibility: 1. General Rules apply. 2. Youth ages 14 and older may pull sport stock classes with written parental consent.  EXCEPTION:  Any youth 12-14 wishing to compete in sport stock class must submit an application to committee for approval by Dec. 31.  To submit an application, the youth must have at least 1 year prior pulling experience. 3. Helmet, full length pants and closed toe shoes REQUIRED. 4. A tractor may be entered only once per class. 5. A sport stock tractor competing in the sport stock class cannot move up a class in the same event. Chassis: 6. Transaxle housing and chassis must be OEM available in a commercially produced garden tractor.  7. No aftermarket multi-range gear box. 8. Engine must be OEM available for lawn and garden.  No automotive, motorcycle, ATV, marine, snowmobile, etc, type engines allowed. 9. Tractor must have stock appearing hood and grill (nose piece).  Switching to another factory sheet metal is permissible. 10. Maximum wheel base is 52 inches. 11. Maximum distance from center of rear axle to farthest point forward is 96 inches. 12. No additional power source attached to drive line. 13. Flywheel and clutch must be shielded with stock shields or 1/8 inch steel or 3/16 inch aluminum 360 degrees. 14. Single cylinder tractors not running stock side panels need to be shielded with 1/8 inch steel or 3/16 inch aluminum plate opposite cam side height and width of block.  This plate would need to be mounted with two bolts to the frame and at least one bolt to the head. 15. Wheelie bars must be rigid in all directions and able to support the tractor and driver in the heaviest class.  Each skid shoe must be a minimum of 1.5”x 2” or the use of 5” round wheels 1” wide is allowed.  Tractor must have 2 skid shoes or 2 wheels.  The wheelie bars must be a minimum of 5” from the rear most part of the tire and maximum of 10”.  The bars must be a maximum of 5” from ground to bottom of skid shoes or wheels.  A vertical bumper bar 6” in height in rear most position is required.  Weights on back of tractor must be contained up to 1” before end of the wheelie bars. (Refer to diagram in back of book) 16. Maximum hitch height is 13”.  Must provide own clevis or straight flat plate with 1 ½” hole with a dead man zone of 3” on each side of the hitch.  Hitch must be rigid in all directions.  The kill switch must be centered approximately 10”-12” above the hitch in this area.  (Refer to diagram in back of book) 17. ALL TRACTORS MUST HAVE a minimum of 1 lb fully charged fire extinguisher on board in reach of operator.  A functional gauge on the fire extinguisher is REQUIRED. 18. ALL TRACTORS MUST HAVE rear fenders extending a minimum of 4 inches out over the tires.  OEM fenders are acceptable.  It is recommended that foot well and rear fender be attached to avoid the possibility of operator’s foot being pulled through to come in contact with tire. 19. ALL TRACTORS MUST HAVE at least a 3 inch seat back. Engines: 20.  a. One or two cylinder, flat head or overhead valve, naturally aspirated, carbureted, cast block, four cycle gasoline engines. b. Naturally aspirated Diesel engines up to 42 cubic inch and up to 3- cylinder allowed. 21.  Engine blocks must remain stock appearing on the exterior. 22.  Stock intake manifolds must be used on all engines. 23. In all engines the following engine components must remain in original position: a. Crankshaft b. Camshaft c. Valves d. Rocker arms. 24.  Stock valve diameter must be maintained for all engines. 25.  Stock  crankshaft  stroke  must  be  maintained  for  all  v-twin  engines.    26. Engine RPM’s must be controlled by mechanical governor.  Maximum limit: 4500 RPM for Gasoline engines and 4000 RPM for Diesel engines. 27. ALL TRACTORS MUST HAVE a functional breakaway kill switch to cut ignition and fuel pump.  Diesel engines MUST HAVE air shut off to cut the engine, as well as electronic fuel pump disconnect .(Refer to diagram in back of book) 28. All Tractors must have a “dead man” throttle.  Throttle must return to the idle or closed position when the pedal or lever is released. 29.  Exhaust must discharge within 10 degrees of vertical. 30.  All flat head engines must have head plates or straps.  Minimum of ¼ inch x 2 inch steel or ¾ inch x 3 inch aluminum. Gasoline Powered Tractors: 30.  Overhead Valve engines have a maximum of 38.8 cubic inches.  No aftermarket cylinder heads for overhead valve engines. 31.  Flat  head  engines  have  a  maximum  total  engine  displacement  of  45  cubic  inch.    Billet  aluminum  heads  are  allowed  for  flat  heads.    32. Carburetor airflow must be controlled by a throttle shaft actuated butterfly.  Carburetor must be stock appearing, lawn/garden type. 33.  Intake tract must pass thru a maximum 1.2 inch diameter round restricted area or equivalent. Explanation: a. One barrel carburetors may be a maximum 1.2 inch diameter. OR b. Two barrel carburetors may be a maximum .866 inch diameter per barrel AND c. No air may enter intake tract downstream of the 1.2 inch (or equivalent) restriction. 34.   No electronic rev limiters 35. Gasoline only. Diesel Powered Tractors: 36.  Engine blocks must be clearly marked with the engine model number.  Valve cover tag with engine displacement must be in place for engine identification. 37.  Diesel fuel only 38.  No other injection will be allowed. (water, propane, alcohol, etc.) 39.  Stock manifolds only. 40.  No ice boxes or intercoolers. Tires and Wheels: 41.  Maximum tire size: 26 x 12.00 x 12