Pro Stock Tractor Rules


Tractor General Rules

  1. All engine blocks must remain in original location as intended by the manufacturer. Sheet metal to be stock length and location must be stock appearing.
  2. Tractors must have grill and hood in place as intended by manufacturer.
  3. Tractors must have stock block, agricultural type block, OEM replacement block. No automotive blocks permitted. Maximum of 8 cylinders permitted.
  4. Maximum wheelbase is 114” and maximum length is 13’ from the center of the rear axle to forward most part of the tractor.
  5. Up to four (4) turbo-chargers permitted, but only three (3) pressure stages permitted.
  6. All turbocharged engines on tractors will have one cable totally surrounding the engine block and head. The cable will consist of ⅜” diameter and located between the first and second cylinders. Cable must pass through the manifold areas. Cable will have four (4) to six (6) inches of slack. There will be a minimum of four (4) clamps at all splices. Maximum of 2 valves per cylinder.
  7. A deflection shield between driver and engine from top of hood and top of transmission housing or clutch housing is required. Deflection shield will go from side shield to side shield. This will help provide a barrier during a flash fire.
  8. All tractor engines are required to shield all rotating mass mounted on the front of the crankshaft. Shield to be frame rail to frame rail by a minimum .125 aluminum or steel fastened to the frame on each side by two evenly spaced bolts. (⅜-inch Grade 5 minimum.)
  9. All tractors are required to have an approved bell housing blanket that meets the following specifications: 20 ply ballistic nylon or 20 ply Kevlar style 713 betting construction. At least seventeen (17) inches wide and long enough around the bell housing with six (6) inches of overlap, secured with a two (2) inch wide nylon web straps, with a steel “d” ring and to be tied in a saddle cinch and with four (4) two inch nylon webs retaining strips, each at the front and back of the blanket.
  10. All tractors will run a safety tie bar system or a one-piece frame rail secured to the rear axle housing.
  11. . Tie bars will be mounted with at least four (4) axle housing bolts.
    . Tie bars will extend forward of bell housing area and be fastened to side of the block with a minimum of two (2) ⅝ bolts.
    . Tie bars will be of sufficient strength to support weight of the tractor with the bolts used to split tractor removed.
    . All safety blankets will be mounted inside safety tie bar system.

11. On cast iron OEM chassis a ½” steel spacer plate is permitted for clutch clearance.

Component Chassis:

  1. Component tractors are permitted. All new component tractors must have approval of sheet metal and engine combination.
  2. Front nose of the crankshaft can be no lower than 4” of the center of the rear axle.
  3. Aftermarket chassis replaces OEM clutch housing with a SFI 6.2 or 6.3 bell housing in its place.
  4. The engine placement can be no further forwards than 60” from the centerline of the rear axle to the rear of the block.
  5. No four-wheel drive tractors will be permitted.
  6. All tractors with a competition weight of 7,000lb to 10,000lb will require a 47.1 SFI Spec rollover protection.

Pro Stock Tractor Rules

1. Maximum weight permitted is 10,000lb.
2. Maximum cubic inch limit is 680. Maximum of 8 cylinders permitted. Acceptable blocks must have come from 2WD tractors. OEM aftermarket replacement blocks permitted, which will follow these guidelines:

. 6 cylinder maximum
. Acceptable blocks must have came from 2WD tractors.
. Camshaft must remain in the OEM location. No overhead cams permitted.
. Fuel injection pump must remain in OEM location.
. Height maximum - center of crankshaft to cylinder head surface not to exceed one inch over OEM dimension (block, gaskets, deck/spacer plates.)
. Engine block must have marking/casting indication from manufacturer.
. Block may be inspected by official before assembly and being placed into service.

3. The only acceptable fuel is diesel fuel.
4. No combustible agents allowed in water injection.
5. One turbo-charger is allowed, as is one pressure stage and one air compressing device. Turbo-charger’s compressor housing must be wrapped with a Kevlar style blanket. Exhaust elbows are recommended to be schedule 10 pipe.
6. Intercoolers are permitted.
7. Maximum tire size should not exceed 24.5 x 32.
8. All Pro-Stock tractors will require a 47.1 SFI Spec rollover protection.
9. All other tractor rules apply.