NORTHWEST LIMITED PRO-STOCK/SUPER FARM TRACTOR

1.        This class shall consist of tractors that conform to generally accepted Super Farm and Limited Pro-Stock rules.

2.        Weight:

a.  Super Farm --- 9300 lbs.

b. Limited Pro-Stock (p-pumps) --- 9300 lbs.

c.  Limited Pro-Stock (a-pumps) --- 8500 lbs.

d. The weight advantages for these sub-classes of tractors may be adjusted accordingly at any time, in an effort to achieve parity, by the Northwest Board of Directors.

 3.        Engine:

a.        Engine sub-groups of tractors shall be as follows:

i.         Super Farm

(1)     Turbo --- 3” intake and 3” exhaust measured at the face of the wheel

(2)     Engine CID --- 640”

(3)     Fuel Pump-maximum “P” pump

ii.        Limited Pro-Stock (p-pumps)

(1)     Turbo --- 3” intake and 4” exhaust measured at the face of the wheel

(2)     Engine CID --- 400”

(3)     Fuel Pump-maximum “P” pump

iii.      Limited Pro-Stock (a-pumps)

(1)     Turbo --- unlimited

(2)     Engine CID --- 540”

(3)     Fuel Pump-maximum “A” pump

 b.       Engine cylinder head must be OEM for that brand of engine.

         c.        No overhead cams allowed.

 d.       OEM stock intake and exhaust manifolds for that brand of engine.

 e.        Turbocharger:

i.         Alterations for turbo mounting are allowed.

ii.        No altering of a housing to accommodate a smaller base.

iii.      Intake and exhaust measurements will be taken at the face of the wheel.

 f.         Super Farm/Limited Pro-Stock tractors may have one (1) diesel injection pump with only one (1) plunger per     cylinder.  No Sigma pumps allowed.

 g.       Tractor is to use fuel for that make and model of tractor when manufactured.  Water injection allowed, no intercoolers or after coolers.

 h.       Use of gasohol or alcohol is prohibited.

 i.         All turbocharged engines are required to have one cable that must surround the engine block and head.  This cable shall be located between the first and second cylinder through the exhaust manifold port area.  The cable will be a minimum of 3/8” thick with two (2) clamps at the splice.  The cable should allow for approximately 4” of slack.

 j.         Turbocharged engines must have two (2) 3/8” bolts (grade #5) in vertical portion of exhaust pipe(s).  Bolts to be installed 90 degrees to each other, within one (1) inch of each other.

 4.        Clutches:

a.        All clutches and flywheels must be SFI Spec. 1.1 or SFI Spec. 1.2 approved.  NO cast iron.

b.       All SF/LP tractors are required to have an SFI approved, Spec 4.2 bell housing blanket, meeting the following minimum specification:

i.   Seventeen (17) inches wide and long enough to allow for a 6 inch overlap.

ii.  Secured with six (6) 2-inch wide nylon web straps with steel D rings sewn in the length of the blanket.

iii.Four (4) 2 inch wide nylon web retaining straps on both front and back of blanket.

c.        Only mechanically activated clutches are permitted.

 5.        Sheet metal/Wheel Base/Chassis:

a.        Tractor must have hood and grill in place as intended by manufacturer.  All sheet metal is to be stock length and in stock position.  Upgrade to present manufacturer is allowed but can not cross original manufacturers lines.

b.       Tractor must retain stock appearance.

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

d.       Wheel base rule will apply to the original chassis not the model upgraded by the sheet metal.

e.        Maximum wheelbase will be 114 inches unless originally produced with a longer wheelbase.  Maximum length is 13 feet from the center of the rear wheel to the forward most portion of the chassis.

f.         The chassis shall consist of stock or OEM engine block without alterations for chassis mounting with stock transmission housing or manufacturer replacement and stock final drive housing or manufacturers replacement.

g.       Engine must remain in original location as intended by the manufacturer.

h.       All engines must be secured and held rigid to an OEM chassis.  The engine cannot move independently of the transmission or rear end.

i.         OEM engine blocks cannot be modified except for repair or mounting pumps.

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

k.        Clutch housing, transmission case, rear-end housing, and axle housing OEM; no aluminum replacement parts allowed.

l.         Safety tie bars mounted to the rear axle housing with at least four (4) axle housing bolts and extending forward of the flywheel area and fastened to the side of the block or main frame with at least two (2) 5/8” bolts; OR a one piece frame extending from front of tractor to rear axle housing mounting bolts.

m.      Wheelie bars required.  Wheelie bars must extend 32” in front center line of axle.  Pad must not be more than 10” off ground; pad must be a minimum of 5” x 5” square.  Wheelie bars must support tractor in heaviest class pulled.

 6.        Draw Bars:

a.        Draw bars must meet either ATPA or NTPA listed standards and be constructed so that in the event of draw bar breakage the draw bar supports do not pull from a top link or brace above the centerline of the rear axle of the vehicle.

b.       Draw bar height for SF/LP tractors shall be 20 inches in height and 18 inches in length.  Draw bar height or distance from center of rear axle cannot change during the pull.

c.        Draw bar may not be connected to the wheelie bars.

d.       The primary draw bar must be 8 inches above the secondary draw bar for those vehicles with a second draw bar.  The hole in the second draw bar must be covered if not in use.

 7.        Tires---Maximum tire size 24.5 x 32.  Maximum of 48 lugs.

 8.        Shielding

a.        A deflection shield is required on both sides of all engines.

b.       Shielding must extend the complete length of the block casting from the sheet metal hood to 2 inches below bottom center of the crankshaft throw and be securely fastened.  It is recommended that quick release fasteners be used, such as Dzus type or cotter pin type hood pins.

c.        Shielding must be a minimum of .060 inches thick steel or safety blanket materials.

d.       Solid frame rails with no holes may serve as part of or all of shield, providing they cover the required block area.

e.        A metal deflection shield is required between the driver and engine from the top of the hood to the top of the torque tube or transmission housing or clutch housing from side shield to side shield.  This also serves as a fire shield in case of a flash flame out.

 9.        NO four-wheel drive model tractors are eligible for this class.

 10.     All vehicles are required to have working kill switches.

 11.     All drivers are required to wear DOT approved helmets and fire suits.

 12.     All vehicles are required to have a working fully charged fire extinguisher on board.

 13.     All vehicles will have roll cages and seat belts.  Seat belts must be worn.

 14.     Vehicles with diesel or fuel injected ignition engines must have a three-way dump fuel shut off valve.  The control is to be within easy reach of the driver as is the normal fuel shut off on a diesel fuel pump.  Diesel engines must also be equipped with an emergency shut down air shut off at the intake that can be operated from the driver’s seat.