6250 LB. LIGHT LIMITED SUPER STOCK
Blocks and crankcase shall be the same manufacturer or factory replacement.
Engine must match brand of tractor.
Rear of engine must be in stock location for make and model of rear end and transmission housing, with a maximum tolerance of a 1” adapter plate.
A 1% tolerance will be given on cubic inch limitations to allow for normal engine wear. 4-1 All engines will be checked for cubic inch before the first pull.
No V-8 Engines permitted.
Maximum of 315 cubic inches for twin turbo charged diesel engines. Intercoolers allowed. No MAF enhancement.
Maximum of 410 cubic inches for single turbo charged diesel engines. Intercoolers allowed.
Maximum of 470 cubic inches for single turbo charged diesel engines. No intercoolers allowed.
Maximum of 370 cubic inches for single turbo charged alcohol engines. No intercoolers allowed.
Cylinder heads must be the OEM manufacturer casting for said tractor and engine block or factory replacement block at the time of manufacture. Original casting must be retained. Porting and polishing of the original ports is allowed. Modifications to the cylinder head(s) to accept for billet, casted, recast, molded or any other kind of insert is NOT allowed. Cylinder heads limited to two valves per cylinder. No overhead camshafts allowed.
Maximum thickness of a 1" plate is permitted between the top of the block and the bottom of the cylinder head.
Turbocharger(s) shall not exceed a 3” inlet and a 4” outlet measured at the face of the wheels. No “step down” intake housing, exhaust housing or wheels of any kind allowed. The intake wheel and exhaust wheel must protrude into the maximum allowed inlet and outlet dimensions at least 1/8”. No secondary source of air and no slots of any kind allowed. Housing slots must be permanently disabled by being welded shut. No temporary inserts or plugs allowed.
12-1 No MAF enhancement on larger than 310 alcohol tractors, all plugs will be welded non- removable.
Diesel and less than 310 cubic inch alcohol single turbo can run MAF enhancement.
Allow diesel only 315 and under 2 (3” intake) chargers. No MAF enhancements.
Turbocharger(s) must be under stock hood or shrouded end to end and 360 degrees around with .060” steel or heavier. Turbocharger(s) must also be shrouded if under a fiberglass or plastic hood.
Use of supercharger(s) is not allowed.
The largest fuel system allowed is a “P”-pump with one plunger per cylinder and one injector per cylinder. No electronically controlled fuel system allowed.
No secondary source of fuel (liquid or gas) or oxygen enhancer allowed.
Water injection allowed with oil lubricant only. No additives allowed in injection water. Water will be subject to testing.
Exhaust must be discharged vertically. No rain caps or curved pips at outlet allowed. Exhaust pipes must be securely fastened to tractor.
Exhaust pipes must have two 3/8” grade five bolts set within 1” at 90 degrees to each other at least one foot below opening in the exhaust and two 3/8” grade five bolts set as close as possible to turbo before upward elbow.
Harmonic balancer must be shielded with at least 1/8” metal underneath the front of the block and secured to the frame with four 3/8” bolts.
Engines must have one 3/8” safety cable completely surrounding the block and head passing between the first and second cylinders, through the exhaust manifold port area, with a minimum of two clamps at all splices with 4-6 inches of slack.
Must have a spring loaded closing mechanism air shutoff. To be deemed acceptable, when activated. The shutoff mechanism must prevent boost of engine. The kill switch must be mounted securely to the back of the tractor and have a 2 inch diameter ring (minimum 1/8“ thick). Operator must also be able to operate from the driver seat.
Fuel system must have manual three-way dump valve installed ahead of the injection pump. To be operated by the operator from the driver seat.
Must have “Dead Man” throttle with two return springs that automatically returns to idle when released by operator.
No mechanical fans allowed.
Flywheel will be made of steel or aluminum and be SFI approved. Absolutely no cast iron allowed. All clutch assemblies will be steel and SFI approved. No cast iron.
Maximum length 13 feet. Measured from center of rear axle to forward most point. Excluding tow hook.
Maximum wheelbase 114”.
OEM tractor rear end and transmission housings only will be accepted, no component tractors allowed.
Allow air bags and/or coil over shocks on the front of tractor as long as they cannot be adjusted from the seat.
Allow tractors with cast tub (belly)-type frame (ie., 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.
Skid plates for all tractors in class.
Skid plate must be mounted in-line with each frame rail and extend from the center of the front axle 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 jack. Maximum ground clearance is bottom of wheel rim not to exceed 4 inches with front tires in normal operating position.
Safety tie bars will be required in all tractor classes. Tie bars will be from frame rail to rear axle housing and be capable of supporting the tractor with all bolts removed from transmission housing.
All hitches will be minimum 3 ½ inches long X minimum 3 inches wide at the hook point. Lateral thickness of hitch will be maximum of 1 ½ inch minimum 1 inch cross-sectional thickness. Hitch will be no shorter than 18” measured from the center of the rear axle to the hooking point.
Maximum hitch height 20”.
Roll cage is required to meet SFI 47.1 requirement. 5 point SFI harness is required.
Wheelie bars; independent of hitch. Must be able to lift tractor with jack under pad in heaviest class tractor participates in. Pad to be no more than 10” above ground and should be minimum length of 32” from center of axle when set at the 10” maximum height.
Maximum tire size 30.5 X 32
Minimum tire size 18.4 X 38
Acceptable fuels are diesel fuel, alcohol and gasoline.
No oxygen carriers or combustion accelerators will be permitted.
No ether starting aid can be on tractor.
Weight for the class is 6250 pounds.
All tractors will be weighed in and certified before the start of the season.
All tractors must carry at least 200 pounds of moveable weight.
Complete fire suit and fireproof gloves are required. Must meet SFI spec 3.3c. No tennis shoes are to be worn, must have good work shoes or fire shoes. All drivers will be required to use a SFI approved 3.3 neck collar and head sock.
All competitors will wear a full face helmet. Snell 2005 rating or better.
All tractors will have SFI approved clutch/flywheel assembly. No cast iron.
All tractors will use a six buckle SFI approves safety blanket.
A safety light system is required. A white automotive quality light, minimum of 2” in diameter, must be directly mounted above or below the safety kill switch at the rear of the tractor.
The light is to be activated by a shift lever such that it will only be illuminated when the tractor is reverse or neutral.
Must have at least 2 ½ lb. Fire extinguisher and be convenient to the operator.
Random testing at any time.
SCWTP General Pulling Rules will also be enforced.