HSTPA Light Limited Super Stock Rules
All OEM chassis Pro Stock rules, including shielding, safety and SFI requirements, apply to this class plus the following rules.
- Tractor weight will be 6250lbs. (50lb variance will be given at the scales)
- Engine must match brand of tractor. Engine crankcase, block, and cylinder head must be of same manufacturer or factory replacement and can be used in any agricultural transmission and rear end that used that brand of engine or through its company mergers used that brand of engine.
- Must be OEM engine block, no Billet steel or aluminum blocks.
- 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.
- No V-8 Engines permitted.
- No Overhead cams allowed
- Maximum allowed “P” pump. Only one plunger per cylinder allowed.
- No electronically controlled fuel system allowed.
- No secondary source of fuel (liquid or gas) or oxygen enhancer allowed.
- Water injection allowed
- Computer can only be used for data acquisition, may not be able to control engine timing, or fuel delivery. No traction control.
- Maximum of 315 cubic inches for twin turbo charged diesel engines with Intercoolers. (Turbo(s) must be staged) o This engine combination can run a maximum of two (2) 3X4 smooth bore turbo(s). No MAF enhancement.
- Maximum of 360 cubic inches for twin turbo charged diesel engines and no intercooler or after cooler allowed. (Turbo(s) must be staged) o This engine combination can run a maximum of two (2) 3X4 smooth bore turbo(s). No MAF enhancement.
- Maximum of 410 cubic inches for single turbo charged diesel engines. Intercoolers allowed. This engine combination can run a maximum of one (1) 3X4 turbo with MAF enhancement. o 0.200 MAF enhancements o No forward facing MAF.
- Maximum of 470 cubic inches for single turbo charged diesel engines. No intercoolers allowed. (The 478CI Hercules engine will be legal to run in its factory combination 0% variance on CID)
-This engine combination can run a maximum of one (1) 3.4X4 smooth bore turbo.
Note: For the 2018 season a single 3X4 turbo with MAF enhancement will be legal for the 470CI diesel engine, Max of .200 MAF with no forward facing enhancement. The 3.4X4 smooth bore turbo is on a trial basis and will be reevaluated at the end of the season. In the 2018 season this engine combination will move to only a smooth bore turbo.
- Alcohol Engine maximum of 370 cubic inches for single turbo charged alcohol engines. No intercoolers allowed. This engine combination can run a maximum of one (1) smooth bore 3X4 Turbo
- All turbo compressor and exhaust wheels must protrude into the housing no less than 1/8th of an inch. The compressor wheel must measure no larger then 3-inch at the face of the wheel.
- Diesel engines that will be allowed to run a 3.4X4 smooth bore turbo, the compressor wheel must protrude into the housing 1/8th of an inch and the compressor wheel must measure no larger then 3.400” at the face of the wheel.
- No superchargers allowed.
- Cast iron OEM cylinder head for that brand and model engine. No billet or re-cast cylinder heads allowed.
- Maximum of 2 valves per cylinder. Valves must maintain the factory angle, lateral movement of valves only. Valves must seat in the bottom of the OEM head on all 6cylinder engines.
- One spark plug per cylinder ONLY.
- Maximum of one (1) deck plate will be permitted between the top of the block and the bottom of the cylinder head, with a maximum thickness of 1 1/8th inch.
- Maximum length 13 feet measured from center of rear axle to forward most point, excluding tow hook. Maximum wheelbase 114”.
- No type of front end suspension allowed, swivel axle front ends will be accepted.
- All housings must stay in place, bolted ridged in all other chassis.
- Auxiliary transmission will be permitted.
- Maximum tire size 30.5 X 32 , Minimum tire size 24.5 X 32