Sport Stock

a) Tires:

· Any brand, any cut

· Max size 26-12 x 12

b) Engine:

· Stock engine stroke, bore may be cleaned up .030”

· No pop-out pistons

· .324” valve lift, open duration

· Stock valve head diameter(1.380 intake 1.125 exhaust for 10&12 hp, 1.380 intake 1.380 exhaust for 14&16 hp)

· Stainless steel or titanium valves are permitted

· Grinding of valve stems permitted

· Porting and polishing is permitted

· Steel crank optional

· 4 bolt rods are permitted, must remain stock length

· Stock OEM pistons

· No welding of the head, no recast or billet heads

· No larger than a 1” venturi

· No velocity stacks

· No carb spacers

· Carb must be bolted to the block with one stock gasket and no more.

· Steel flywheels are required

· Any ignition system permitted(point/electronic, crank trigger, etc.)

c) Fuel:

All tractors must run ALCOHOL!!!

d) Driveline:

· Open or locked rear axle permitted

· May use aftermarket gears

e) Chassis:

· 52” wheel base

· 13” hitch height

· Dead man throttle and a fire extinguisher are required. 3-B

· Must have working kill switch mounted to the rear of the tractor, must be able to shut off engine and electric fuel pumps. 3-A