1. Tractors must be agricultural tractors having chassis, engine, clutch, transmission housing, differential housing, transmission, hood and grille of one manufacturer. O.E.M. cylinder head must be for series engine used - no re-cast, no aluminum, no overhead cams allowed. Engine, clutch, transmission, and differential housings, must be bolted together as one unit. All bolts connecting all housings must be in their stock location - OEM length & location from rear end housing to front of engine. No component powertrains.
2.Engine size maximum 540 cubic inches.
3.Diesel fuel only - no accelerants. Water injection is permitted - no accelerants.
4.Injection pump to be one "A" type only (German Bosch only and limited to one plunger per cylinder. One injector per cylinder - the "A" pump is to be the only source of fuel. No billet pumps or housings allowed. Tractor must have fuel dump valve.
5.Homemade engine adapter plates are not allowed.
6.Tractors allowed one turbo charger LIMITED TO 4.5 INCH OUTLET I.D. Manifold pressure to be single stage only. No intercoolers allowed.
7.No hood alterations allowed, except by approval.
8.Any turbo charger not under the hood must be completely shrouded, except for inlet and exhaust pipe, with steel 1/16" or .060" thick or thicker - 360 degrees.
9.All fans must be factory shrouded or shrouded with steel 1/16 thick - 360 degrees.
10. All exhaust must discharge upward with a minimum pipe length of 18" from the hood line. No rain caps. Exhaust pipe must be cross-bolted with two 5/16" bolts in the horizontal pipe within 2" of exhaust wheel and two 3/8" bolts in the vertical pipe.
11.Seat must be a 5 point harness acceptable (racing style).
12.Maximum tire size 24.5 x 32". No radials.
13.The use of torque converters, automatic shifts are permitted. Automatic transmissions must have a positive reverse gear lockout. Steel or aluminum flywheels are required.
14.Harmonic balancer to be shielded to be contained within the vehicle.
15. Tractors must have working air shutoff and deadman's throttle. Throttle must have 2 return springs. The air shutoff cable must activate the air shutoff to the engine. The air shutoff cable must be a positive-type enclosed cable. The shutoff cable must have a minimum 2" diameter solid ring, with minimum 1/8 cross section thickness, attached to it. Air shut off must also be able to be operated manually (by the operator from the seat of the tractor).
16.Tractors must have approved clutch/transmission safety blankets and engine side shields. Side shield material to be minimum 060" in thickness. Plastic or fiberglass hoods must be shielded in the turbo area.
17.The frame and weights must not extend any further than 13' from center of the rear axle to further most point - excluding tow hook. The wheelbase must not exceed 114"
18.Hitch height is 20". Hitch length 18" minimum, from center of axle to hook point. Drawbars must be rigid, in all directions. No movement is allowed while pulling. HITCH HOLE TO BE 3.75" x 3.0". Drawbars must be within 10 degrees of parallel to the ground. Hitch must be horizontal - not vertical. No cast drawbar components.
19.Front skid bars are required.
20.Stabilizer bars are required and to be constructed in accordance with the following:
Pads on bottom of bars to be a minimum of 5 in. sq. pads. Pads to be a minimum of 32" rearward from the center of the rearend housing. Pads maximum of 10" off the ground. Do not connect hitches and stabilizer bars. Outside to outside length of pads to be a minimum of 20". Minimum 12" high bumper bars - top to be fastened to stabilizer bar framing. Bars must support weight of tractor for weight class being pulled.
21.Tractors must have a shield between the driver and the tires that consists of a solid barrier between the driver and any part of the rear tires. The barrier must be able to sufficiently support the weight of the driver and must extend a minimum of 6" horizontally at the top, and be a minimum of 36" wide at the top.
22.Tractors must have working rear wheel brakes.
23.Tractors must have wide front axles. Front wheels must track within rear wheels.
24.Frames or weights must not extend rearward beyond the rear tires or exceed 12" beyond the width of the rear tires. No weights on vehicle seat or deck or within 8" of drawbar hook point.
25.Tie bars required from front of clutch housing to rear axle housing.
26.Fire extinguisher is required.
27.Driver must wear firesuit and helmet.
28.Vehicle must have a rollover protection cage that is at least as high as the top of the drivers head/helmet. Rollover protection must be fastened at least two points to the rear axle housing. Rollover protection must be able to lift one rear wheel when pulled horizontally from the top of the bar/cage without damage to the rollbar/cage. Five point safety harness required.
29.All puller's must be signed up 30 minutes before pull starts!