Pro Altered Class (V-Twin Stock Altered)

1. All general rules apply.
2. Engine shielding rules: 1/8 in. steel or 3/16 aluminum on external side of cylinder extending from head gasket to frame.  Shield must be attached to frame at the bottom and to the flywheel shield at the top to make rigid.
3. Maximum overall length will be 96 in.
4. Maximum wheelbase will be 56 in.
5. Maximum weight will be 1000 lbs. and 1050 lbs.
6. Maximum hitch height will be 13 in.
7. Engines: Must be a commercially available lawn and/or garden tractor engine.  V-Twin type configuration, Single-Cylinder OVH, Single-Cylinder flat head and opposed twin flat heads allowed.
8. Maximum engine size will be as follows: V-Twin OVH=METHANOL 45 cubic inches; OVH=48 cubic inches; Single.
9. Maximum valve size for all makes of V-Twin OVH METHANOL engines will be as follows: Intake Valve=1.325 in.?Exhaust Valve 1.170 in.  V-TWIN VP C-12 ENGINES=open valve size. Single Cylinder OVH Intake Valve=1.437 in.?Exhaust Valve 1.437 in. All flat head engines-no valve limits.
10. Valve Lift: no restrictions.
11. Cylinder Head: Must be stock appearing cast head.  Opposed flat head twins and single cylinder flat heads can run billet heads.  OVH V-TWIN VP C-12 ENGINES must run factory OEM heads with no external modifications done to the heads.  Valve cover spacers allowed.
12. Carburetor: Limited to one (1) carburetor with one (1) venturi with one (1) throttle butterfly.  Maximum venturi size will be 1.200 in. No air entering after the 1.200 in. restriction, except for the OVH V-TWIN VP C-12 ENGINES can run same as above.  1.200 in. venturi, no air entering after 1.200 restriction.
13. Intake manifold: Steel flywheel mandatory, along with the general flywheel shielding rules of 1/8 steel or 3/16 aluminum 360 degrees.

Super Stock Rules

1. Single Cylinder Super Stock is defined as any tractor having one cylinder, air cooled four cycle, flat head, tow valves same side of engine.
2. Any type of Naturally Aspirated induction is permitted.
3. Methanol only.
4. All tractors must have hood and grill.
5. Wheelbase 56 in. maximum.
6. Top placing tractors will be checked for, but not limited to: Fuel and Cubic Inch Limit. CU IN: 50.500