United States Association of Pullers Tractor and Truck Pulling in West Tennessee, Kentucky, Alabama
United States Pullers Association Tractor and Truck Pulling in West Tennessee, Kentucky, Alabama, Arkanas and Missouri
Annoucements from United States Pullers Association

United States Association of Pullers Class Rules

Super Stock
Super Farm
Hot Farm
Farm Stock
6000 Pro Field/6200 Small Block Hot Rod

Pro-Stock Diesel

General Rules

USA Pullers has adopted the NTPA Rule Book with some amendments and modifications.

ALL competitors must have a valid USA Pullers competition license and a valid USA Pullers vehicle notification.

We have adopted NTPA levels of points accumulation, competitor eligibility, general rules where applicable, event procedures and requirements, contest operations, causes for disqualification, violations, penalties, protests and additional classes. This rulebook can be found here.

Safety (All vehicles except Farm Stock)

Stabilizer Bars

The stabilizer bar must extend a minimum of 32 inches behind a line drawn from the center of the wheel to the ground. Pad must not be more than 10 inches off the ground at 32-inch pont and to be measured during which check before competition.

The stabilizer pad must be a minimum of 5 inches square (no wheels allowed on big tractors) with a minimum of 20 inches allowed from the outside of one pad to the other.

Stabilizer bar and bar assembly is not to be mounted to the drawbar and drawbar assembly.

Note: No crossbars between stabilizer bars allowed behind point of hook.

Big Tractors:

A. Stabilizer bars are required.

B. In addition to stabilizer bars, there must be a brace that extends vertically 12 inches from the rear most tip of skid pad.

C. There must be a support brace extending inward to frame, axle or top of the stabilizer bar arms.

D. Vertical brace should extend rearward a minimum of 2 inches from radius of rear tire.


Tractors are required to have a SFI Spec. 4.2. bell housing blanket that meets the following minimum construction specifications.

A. Seventeen inches wide and long enough to wrap around the bell housing with at least a 6 inch overlap.

B. Secured with six 2-inch wide nylon web straps with a steel D-Ring on one end and sewn the length of the blanket (except for overlap area) and long enough to pass back through the D-Ring and be tied in a saddle cinch.

C. Four 2-inch nylon retaining straps each at the front and back of the blanket.

Skid Plate, Big Tractor Classes

Skid plate must be mounted inline with each frame rail and extend from the center of the front axel forward (on both sides) equal in strength to frame rail material. Skid must be securely mounted and braced to the chassis. Skid plate surface to be minimum of 4 inches wide and 12 inches long with a minimum 6 inch curve when measured from the front most part of rolled edge.

Note: Skid plate must be able to support the weight of the front end when checked with a jack. Maximum ground clearance is bottom of wheel rim not to exceed 4 inches with front tires in normal opening position.

Safety/Rollcage - SFI Certifiable

A. If senior track official and tech official feel that a vehicle is unsafe, they have the right to not allow a vehicle to hook.

B. All tractor classes must utilize an SFI roll cage with a five-point harness. Roll cage must be certified.

Note: The following SFI specs will apply: SFI 47.1 - 8,000 - 10,000 pound classes. SFI 47.2 6,300 pound classes. Front diagonal braces on all roll cages must be shielded with a minimum of .060 steel or aluminum on the inside of drivers compartment to prevent any part of competitor’s body begin caught upon exit.

C. All vehicles with roll cages are required to have a quick release, removable or swing away steering wheel for ease of extraction of driver in event of injury.

D. All controls in drivers compartment i.e. fuel shutoff, air shutoff, ignition, throttle, shifter must be accessible while strapped in five-point harness.

E. All pulling vehicles must be equipped with a minimum of 2.5 pound dry-powder type fire extinguisher, fully charged with gauge in working condition and convenient to operator.


Diesel engines are required to install a manual three-way dump valve, which can be operated from the dash panel while strapped in the seat, ahead of the injection pump.

Super Stock Tractors

A. OEM Chassis shall consist of the following:

1. Engine block must remain in original location as located by manufacturer.

2. Only engines considered legal to be used in Super Stock division must be available in two-wheel-drive farm tractors (This applies to both OEM and Component type.)

3. The stock transmission housing or manufacturer's replacement and the stock final drive housing or manufacturer's replacement.

4. Allow tractors with cast tub (belly)-type frame (i.e. Oliver, Cockshutt, White) to remove complete frame from front of transmission housing. Engine and clutch housing to remain in original location and mounted solid as intended by original manufacturer.

5. The OEM engine block of given brand to remain consistent with that brand of transmission and rear housing as well as sheet metal. It cannot be modified externally, except for normal repair or for mounting of fuel injection pumps.

6. Internal webbing and water jacket must remain intact with provisions to rebore engine block be provided.

7. An external holddown device is allowed to hold head to block. This device connects top of head to bottom of block and must remain behind the side shields. (Note: This device does not replace the safety cable, which must remain in place.)

8. All engines must be secured and held rigid to OEM chassis. Engine cannot move independent of rear end/transmission housing.

9. The chassis and frame must remain stock from the rear of the engine block to the rear of the tractor.

10. The grill may be altered to allow air intake, but not totally removed.

11. The clutch housing, transmission case, rear end housing and axle housing must be OEM, with no aluminum replacements.

12. No auxiliary internal combustion engines are allowed onboard to drive pumps, accessories, etc.

13. Once piece engine main cap bearings allowed. One piece main cap not considered a girdle.

Component Chassis:

14. USA Pullers will allow component tractors under the following criteria:

a. Must install an aftermarket frame with an SFI-6.2 or 6.3 bellhousing to replace the original clutch housing. Must also install an aftermarket transmission and rear end to replace the original equipment transmission and rear end/final drive housing. No cast iron Ag-type transmission or rear end components allowed. Aftermarket transmission and rear end components must by approved by USA Pullers Technical Officials.

b. Primary (and secondary, if used) drawbar and rollcage and five-point restrains harness, must be par to the aftermarket frame structure.

c. Component chassis tractors will be allowed to run any agricultural tractor sheet metal (1960 or newer) with any legal block. Block does not have to be the same brand as sheet metal. The engine block cannot be modified externally from OEM configuration, except for normal repair or for mounting of fuel injection pumps.

d. Engine location on component Super Stock tractors: centerline of the crankshaft may not be below the centerline of rear axle and must be parallel within two degrees in relationship to the ground. (Two degrees equals 7/16ths-inch per foot. This equals approximately four inches of fall from center of rear axle to the 114-inch wheelbase point. This to be measured with tire, hitch and weight in ready to pull position.

e. All engines in component Super Stock tractors to be mounted no farther forward than 60 inches from the centerline of the rear axle to rear of engine block.

f. Crankshaft centerline to be between top and bottom rail of frame. Bottom of frame rail may be no more than six inches below centerline of crankshaft from rear of engine block forward.

g. Component tractors only are allowed to use any agricultural type engine that conforms to sheet metal and cubic inch limits. Diesel engines only to be allowed to use OEM four valve head for that series engine.

h. All tube ladder-type frames must be covered on outside with steel or aluminum 0.060 thick and run in the same plane as the crankshaft.

i. Appearance to remain stock of given brand and model.

j. Driveline shielding same as Modified tractor rules.

k. All component tractors can run a maximum of 114-inch wheelbase, with a maximum overall of 13 feet from center of rear axle to forward most point.

B. Clutches

1. Non-Component Super Stock tractors are required to have an SFI Spec. 4.2 bellhousing blanket.

2. Only mechanically-activated clutches are permitted.

C. Frame/Sheet Metal

1. Tractor must have hood and grill in place as intended by the manufacturer.

2. Sheet metal my be upgraded to present manufacturer upon approval by USA Pullers Technical Services.

3. Sheet metal upgrade may not cross original manufacturer's lines. For example, Case to IH, or Oliver to Minneapolis Moline.

4. Sheet metal to be stock length and in stock location.

5. Tractor must retain stock appearance.

6. The distance from the center of the rear axles to that part of the hood that is farthest forward must be the same length as the model of the upgraded sheet metal.

7. Wheelbase rule will apply according to the original chassis, not to the model of the upgraded sheet metal.

8. Maximum of 114-inch wheelbase unless originally produced with longer wheelbase, in which case stock length must remain. Maximum length of the 13 feet from center of rear wheel to forward-most portion.

9. Super Stock Chassis Rule A:1-9 above will apply according to the original chassis, not to the model of the upgraded sheet metal.

D. Engines

1a. Light Super Stock class is limited to 505 cid. Only two valve per cylinder must be parallel with each other and parallel within 15 degrees of the cylinder wall. OEM canted valve heads allowed. No overhead cams or hemi style heads allowed at any level for the light divisions. No V-Style (i.e. V8, V-10 or V-12) engines allowed. Inline engines only.

1b. Light Super Stock class: Intercoolers are only allowed on Diesel and OEM head alcohol tractors.

2. No overhead cams or hemi-style head allowed.

3. Turbocharged engines are required to have one cable that must surround the engine block and head. This cable must be placed between the first and second cylinder through exhaust manifold port area.

a. Cable must be a minimum of 3/8-inch thickness.

b.Cable must have a minimum of (2) two clamps at the splice.

c.Cable must have approximately 4 inches of slack.

d. Multiple-head engines require one cable per head.

4. Super Stocks are limited to (3) three pressure stages, with a maximum of (4) four turbochargers.

5. Super Stock tractors are limited to (2) two valves per cylinder.

6. Diesel Super Stock division water injection allowed. Intercooler allowed. Use of gasohol and/or alcohol is prohibited.

7. 40 series Detroit engine considered a legal replacement engine for AC 426 engine application with an approved rear engine plate in Super Farm and Super Stock Divisions.

E. Metal deflection shield between driver and engine from top of hood to top of torque tube or trans housing or clutch housing from side shield to side shield. This also serves as a flash fire shield.

F. Tractors Must Have Either:

1. Safety tie bars mounted to rear axle housing with at least (4) four axle housing bolts and extending forward of flywheel area and fastened to side of block or main frame with at least (2) two 5/8-inch bolts, OR,

2. A one-piece frame extending from front of tractor to rear axle housing mounting bolts.

Note: The bars or frame must be of sufficient strength to support weight of tractor with the bolts used to split the tractor removed.

Note: If in question, to be approved by a USA Pullers official.

G. Safety blankets must be on the inside of the tie-bar and the tie-bar must be fastened forward of the rear of the engine block.

H. All ether bottles (or starting aids) must be placed outside the engine compartment.

I. Super Stock tractors that require tools for the removal of side shields must be equipped with an onboard fire control system. Onboard system nozzles must be in engine compartment.

J. Tires

1. 30.5 x 32 with a maximum of 210-inch circumference, whne inflated to 10 psi. Tread width not to exceed 31 inches.

Note: Width determined by manufacturer's size.

K. Safety

1. Vehicle must have a complete firewall with no holes except for controls. Holes not to exceed 1/2-inch larger than control.

2. Super Stock tractors utilizing onboard fire extinguishing system must place one nozzle on each side of engine, inside the engine compartment. Not to be attached to the sheet metal.

L. Weight

1. All three or more turbo alcohol tractors weigh 6200 lbs, All four turbo diesels weigh 6500lbs, and All others weigh 7000lbs.

Super Farm Tractors

Super Farm Tractors going by NTPA 2015 rules with the following ammendments.

A. Engines

Note: The Super Farm class will run under NTPA OEM chassis only (no components) Pro Stock division rules, plus the following:

1. No engines larger than 640 cid. (+ or - 1 percent).

2. Engine head must be OEM agricultural-type for that brand engine.

3. No overhead cams allowed.

4 Manifolds:

a. OEM head and manifolds for same brand block and same series engine.

b. OEM intake and exhaust manifold assembly only. No spacers between manifold and head.

c. No altered or modified manifolds (i.e. tubing or box type manifolds.)

d. No intercoolers/Aftercoolers.

e. If a OEM intercooler manifold is used it must be disconnected from all cooling means.

f. No CO2 or any other means of cooling the air in the piping or manifold. No ice filled or ice cooled devices onboard tractor of any kind. All engine air must enter the inlet of the turbo at ambient air temp and humidity. Inlet air may not be drawn through or across any type of cooling device.

Note: Alterations for turbo mounting allowed.

g. V-8 Engine Configurations: Turbo must be mounted to an OEM exhaust manifold from same brand engine (i.e. Cat engine, Cat exhaust manifold). Fabricated adapter pipes from OEM exhaust manifolds on cylinder heads to turbo manifold sections allowed. Fabricated air inlet manifold from turbo to a single point of entry per cylinder head allowed. Note: This does not change anything for the 6 cylinder engines.

5. Turbos

a. Exhaust bot pattern no larger that 2.750 inches x 3.5 inches, or 69 mm. x 88 mm.

b. No altering of a housing to accommodate a smaller base (e.g. T-18A95 with a small base welded to it.)

c. Turbo, spacer/adapter plate (between Turbo and exhaust manifold) may be a maximum of 3 inches tall with angle permitted with a maximum allowance of 0.130 total gasket material.

d. The compressor inlet measurement to be measured at the face of the wheel a maximum of 3.0 inches. Tips of wheel must protrude into 3-inch opening at least 1/8 inch.

Note: Housing may use a reducer or slug if welded in place. No setscrews or provisions to remove slug. Tips of wheel must still protrude into opening.

e. The exhaust outlet measurement to be measured at the face of the wheel a maximum of 3.0 inches. Tips of wheel must protrude into 3-inch opening at least 1/8 inch.

Note: All exhaust and compressor wheels must be a manufactured one-piece design. Only one intake compressor wheel and one exhaust turbine wheel allowed in one turbo.

No compressor or exhaust turbine wheel can be modified by attaching additional fins or other components to wheel by any method.

Note: Housing may use a reducer or slug if welded in place. No setscrews or provisions to remove slug. Tips of wheel must still protrude into opening.

f. No wastegates or wastegate type exhaust housing allowed including wastegate type exhaust housing with wastegate removed. No air entry after 3-inch opening in compressor or exhausting housing. No MAP width enhancement grooves. No variable geometry turbos.

g. Exhaust turbine height limited to 9.5 inches when measured from the bottom of the exhaust hosing bolt pattern base to the top of the housing.

h. The maximum allowed clearance on each side between turbine wheel and the 3-inch opening when measured at the 1/8-inch protrusion not to exceed 0.050 maximum. This applies to both intake and exhaust sides.

i. Only one pipe and one inlet point from turbo outlet to intake manifold allowed on any inline engine configuration. Air pipe from turbo to intake manifold must be routed in shortest path possible.

Note: Before competing, all Super Farm turbos must be disassembled by the competitor for certification. Competitor must reassemble turbo in front of inspector before turbo will be certified. Turbo assembly will then be sealed on intake and exhaust side with USA Pullers Seal. This seal must be in place before being allowed to compete.

Note: If turbo seal is broken and disassembled fro any reason (repair or maintenance) USA Pullers Tech official must inspect and certify both intake and exhaust sides of turbo at the same time and reseal before being allowed to compete again.

6. The maximum allowed size pump for diesel injection is a p-pump. (No aftermarket housing.) Only one plunger per cylinder allowed.

B. Tires

Maximum 48 lugs allowed on 24.5 x 32 with a maximum of 210-inch circumference, when inflated to 10 psi. Tread width not to exceed 25 inches.

C. Weight

This class shall compete at 9,300 lbs.

Note: All Pro Stock rules, including shielding, safety and SFI requirements, apply to this class.

Hot Farm Tractors

10000 lb 0 to 600 cubic inch motor small block
12000 lb 600 and above big block which includes John Deere 531 cubic inch motor

A. RPM limit is 3000.

Each tractor is required to have an Isspro magnetic pick up device #019R8906. This is available at Schied Diesel, 1-800-669-1593.

B. Tire Size

Tire size is limited to 20.8x42 or smaller. CUT TIRES ALLOWED.

C. Air Supply Shutoff

Tractors must have an air supply shutoff in front of turbo workable from a kill cable at rear of tractor located 48” above drawbar, off 6” to either side.

D. Stabilizer Bars

Tractors must have stabilizer bars (wheelie). Bars must extend a minimum of 32” from center of rear wheel back. Bars must have a pad of 5” square minimum. Bars must have 20” minimum between the pads. Stabilizer bars must be able to support the weight of the tractor in the heaviest class pulled in. There must be a brace that extends vertically 12” from the rear most tip of the skid pad, and there must be a brace that extends inward to the frame, axle, or top of stabilizer bar arms.

E. Safety Tie Bars

Tractors must have safety tie bars mounted to the rear axe housing with at least 4 axle housing bolts and extending forward of flywheel area and fastened to side of block or main frame with at least 2 5/8 bolts. Tie bars must be of sufficient strength to support weight of tractor with the bolts used to split the tractor at the clutch bell housing removal.

F. Safety Blanket

Safety blanket must be on tractor bell housing.

G. Fly Wheel

Steel flywheel and clutch components are strongly recommended, but not required with 3000 RPM limitation and other safety equipment.

I. Roll Cage

Tractors are required to have roll-over protection capable to withstand the weight of the tractor in the heaviest class pulled in. Seat belts are required.

J. Drawbar

Tractors will have a drawbar maximum 20” vertical from ground. Drawbar must be minimum of 18” horizontal length from center of rear wheels back. Drawbars must have a hole for the hitch, oblong shape, 3¾” x 3” wide. No clevis allowed!

13,500 lbs. Farm Stock Tractors

A. 12 mph maximum

B. 3000 rpm maximum

C. 20 inch high drawbar maximum

D. 20.8 x 38 or 20.8 x 42 tires maximum

E. Seatbelt - A waist seatbelt must be fastened when pulling.

F. Kill Switch - Any tractor pulling more than four (4) times in this class must have a kill switch installed.

United States Association of Pullers Truck and Tractor Pullers in West Kentucky, West Tennessee, Northern Alabama, Northeast Arkanas, and Southeast Missouri