Description	Lawn Stock	Altered Mod Stock	Pro Stock	Diesel
Mower Deck	Ability to Mow	None	None	None
RPM	3600	4000	Unlimited	Unlimited
Tire Size	23 x10.5 x12 max	23 x10.5 x12 max	Up to 26 x12 x12	Up to 26 x12 x12
Tire Type	Turf or Ag	Turf or Ag - cuts allowed	Turf or Ag-Cuts Allowed	Turf or Ag- Cuts Allowed
Hitch Height	Factory Draw Bar or Hitch NOT to Exceed 10"	12" Max	13" Max	13" Max
Rear End	S.P.M.	Garden Tractor Type	Garden Tractor Type	Any
Frame	S.P.M.	Factory - No Alumunum	Factory - No Alumunum	Any
Wheel Base	S.P.M.	Front axle not past front/frame	Up to 56"	Up to 72"
Block	S.P.M.	S.P.M.	Factory	Any
Crank	S.P.M.	Factory	Billet OK	Any
Piston / Bore / Stroke	Factory up to 0.030" / Stock	Factory up to 0.030" / Stock	Any	Any
Camshaft	S.P.M.	Factory	Billet OK	Billet OK
Valve	S.P.M.	Factory	Factory	Any
Carb	S.P.M.	Factory	1' Max. Venturi - 1" Spacer OK	Any
Ignition	S.P.M.	Factory	Factory	Any
Exhaust	Stock or Vertical 90°	Vertical 90°	Vertical 90°	Vertical 90°
Kill Switch	Not Required	Yes	Yes	Yes
Throttle	S.P.M.	Stock or Deadman	Deadman	Deadman
Wheelie Bars	Not Required - Optional	Yes	Yes	Yes
Head	S.P.M.	Stock - can be shaved	Stock or Billet OK	Billet OK
Flywheel	S.P.M.	Factory or Steel	Must be Steel	Must be Steel
Shields	S.P.M.	Clutch and/or Belt	Clutch and/or Belt	Clutch / Belts / Engine
Fenders	S.P.M.	Yes	Yes	Yes
Brakes	S.P.M.	Must Work	Must Work	Must Work
Electric Fuel Pump	S.P.M.	S.P.M.	Yes	Yes
Weights / Racks	Wheel Only	Any	Any	Any
Fuel	Gas or Diesel	Gas or Diesel	Gas	Diesel