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Mid Michigan Raceway Park

Pro-Stock / Pro-Truck Rules*

2017 Schedule of Events
2017 Special Events
Test & Tune 2017
Kids Night 2017 / MARFC
Racers Memorial
2017 Corn Harvest
Late Model Rules*
Modified Rules*
Street Stock Rules
Mini-Stock 4 Cylinder Rules*
Pro-Stock / Pro-Truck Rules*
General Rules/FAQ
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Mid Michigan Raceway Park

Pro Stock / Pro Truck Rules

2017 Season

The rules and/or regulations set forth herein are designed to provide for the orderly conduct of racing events and to establish minimum acceptable requirements for such events. These rules shall govern the condition of all events, and by participating in these events, all participants are deemed to have complied with these rules. NO EXPRESSED OR IMPLIED WARRANTY OF SAFETY SHALL RESULT FROM PUBLICATIONS OF OR COMPLIANCE WITH THESE RULES AND/OR REGULATIONS. They are intended as a guide for the conduct of the sport and are in no way a guarantee against injury or death to a participant, spectator or official. The race director shall be empowered to permit reasonable and appropriate deviation from any of the specifications herein or impose any further restrictions that in his opinion do not alter the minimum acceptable requirements. NO EXPRESSED OR IMPLIED WARRANTY OF SAFETY SHALL RESULT FROM SUCH ALTERATION OF SPECIFICATIONS. Any interpretation or deviation of these rules is left to the discretion of the officials. Their decision is final.


Rules apply at all times car is on track. An operational 2-1/2 pound minimum fire extinguisher with gauge visible for inspection purpose is mandatory in each racecar and tow vehicles. Extinguisher must be mounted in a quick release bracket. DUCT TAPE IS NOT AN ACCEPTABLE MOUNTING DEVICE.

Rules apply at all times car is on track. Snell-rated SA2005, SA2010 or SA2015 helmet required. Roll bar padding required in driver compartment. Recommended: Fire retardant padding. SFI-approved full fire suit required. Fire retardant gloves, shoes and neck brace (or head and neck restraint) required. Competitors under the age 18 are highly recommended to use an SFI 38.1 head and neck restraint system due to the young body and developing bones. Right and left seat head supports required if using head and neck restraint system. Recommended: Fire retardant head sock and underwear, collapsible steering shaft. Driver-side window net required, minimum 16 inch by 20 inch ribbon or mesh style, and must be mounted to roll cage so latch is at top front of window. Minimum three inch (two inch with head restraint system) wide SFI-approved five point safety belt assembly required must be mounted securely to main roll cage. Recommended: Safety belts no more than two years old. Any safety equipment physically or visibly wore or damaged must be replaced, regardless of age. All safety equipment must not be altered and must follow manufacturers use, specifications and requirements for installation.


Door number must be a minimum 4" stroke, with 18" height in CONTRASTING COLOR. Roof number must be a minimum 4" stroke, with 20" height pointed to passenger side of car. If we cant read your numbers you will not be scored. A 6" car number visible from the front and rear of the car is required.


Battery may be located anywhere outside the drivers compartment. It must arrive at the track fully charged, and must be securely mounted and the positive battery post must be covered. Starters must be in working order. All cars must start under their own power in the staging area or the will report to the rear of the event. A clearly labeled Battery ON/OFF "KILL" switch must be to the right of the driver and within drivers reach. This is for the Safety Crew to be able to kill power to everything.


Windshield is optional. If used, windshield must be Lexan safety glass, or heavy screen. No Plexiglas. Use of Plexiglas will result in suspension for the night. This is subject to inspection. If no windshield is used a minimum of three windshield bars in front of driver are required. NO MIRRORS ALLOWED.


Hoods must be securely fastened, subject to track inspection. An air cleaner and fire arrestor are mandatory.


No steel body. All fenders, doors and quarter panels must be aluminum. No reinforcing of Aluminum body panels by layering another fender or door underneath.

**After market bodies are allowed.

**Spoilers max width is 68". Spoilers max height is 8". 8" total material, including top lip.

**Spoiler braces may not be squared off. They must come forward and down at an angle to look like the photo above.

**Body must cover at least 1/2 of the tire, but not completely cover the tires.

**Tires must remain visible from front and back of car.

**No side windows or air deflectors allowed.


**Slab side car may have to add at least 50 lb. per side in front of bell housing.

**Maximum overall body width is 74". Max body width at top (Deck and Interior) is 68".

**All body sides from nose to tail on cars will have a visible bow outward and MUST have a break in bodyline.

**Minimum roof height - 45", maximum deck height - 35".

**All roofs must be from 41” - 45” long front-to-rear and 48" - 54” wide side-to-side.

**Rounded and tapered stock appearing fiberglass roofs preferred. Performance Bodies #PER181080

**All roofs must meet all roof dimensions and must be stock appearing.

**No partial roofs, no tilted roofs, no dished out roofs.

**No wings attached to roof or to side posts.

**Must be a full roof.

**No built in fiberglass air dams.

**All roof posts must meet outside of car.

**Front roof supports to be 2"x24".

**Side vents on front roof post can extend back no further than 16" bottom, then straight up to roof for an L-configuration. Side vents must meet outside of car.

**Rear roof post supports must meet outside of car on a flat straight line, and be stock appearing. Top width between 8” - 12”. Bottom width between 18” - 24”.

**Rear roof post must be 32" or greater from the rear of trunk.

**Stock appearing rear sail post must be pre approved, OEM size, and same make and model as nosepiece.

**No Late Model looking noses. Max 2” duckbill.

**Stock appearing nose pieces only. Performance Bodies Classic Dirt Nose (#PERC1X040) and Formed Plastic Sides (#PER20X23X) preferred. (You may need to narrow sides of nose to fit next rule.)

**Nose may be wider than 74”, but you must be able to see the tires by looking down the side of the car or really close to seeing the front tires.

**Noses must be mounted in way that if a square, off of level ground, is touching the nose, at 18” above the ground, the nose must not be any further away, from a level square, than 6”. This is to prevent laid back style down force noses.

**Tires must be visible or really close to being visible from front of car.

**Flares or add-ons to nose piece cannot be higher than front fenders.

**Front bumper and nose must be within 45" from the center of the front wheel and the rear bumper must be within 45" from the center of the rear wheel.

**Front & Rear bumpers not to be wider than body, but must fill area inside panels, tolerance, 2" each side.

**All Pro Stock cars MUST have a rear panel 8" minimum down from deck lid, complete side to side, at 90-degree angle. Must be solid. May have up to a 6" fuel filler door.

**Rear bumper cannot extend more than 8" behind body.

**Bumper heights must be 18" + or - 2" from ground.

**All structural tubing must remain inside body.

**Driver must be able to exit from both sides of car with helmet on.

**Interior of car must be 13 1⁄2" below roll cage minimum and all area of roof, from front window to behind driver’s seat. No area of the interior of cockpit can be less than 13 1⁄2" below the roof and roll cage for safety. Easy exiting of car from either side. Windows must have 13 1⁄2" of clearance straight up and down. No support bars blocking right exit from cockpit allowed.


Stock American engine. No cubic inch limit. The forward most spark plug hole may not be set back any further than a perpendicular line with the center of the upper ball joints for each manufacturer. Roller tip and full roller rockers allowed. No roller camshafts. Intake must have a 1” minimum inspection hole to view camshaft and lifters. NO ALUMINUM HEADS OR BLOCKS.


Mufflers are MANDATORY .100-DECIBEL LIMIT. MUST BE AT THE END OF EXHAUST, must be unaltered muffler, may be added to your current system. NO turndowns. Mufflers must be welded securely in place. Loss of muffler may result in disqualification. Headers are allowed, 1 3⁄4” maximum primary tube diameter header. No Cross Over Collector Headers Allowed. Headers may go over the top of transmission. All 4 exhaust ports from 1 head must be collected within same collector. The 1 3⁄4” maximum primary tube rule must be maintained until the point where all 4 exhaust ports from one head are collected together. Exhaust may not exit through body panels or door.


Distributor must be stock appearing and accept stock distributor cap. No aftermarket dual point ignition or magnetos allowed. No crank fire ignitions. No adjustable ignition control devices. No timing retard controls, or digital gauges (including tach). No electronic monitoring computer devices capable of storing or transmitting information except analog tach. Only stock manufacturer bolt on type parts allowed. Example: MSD or Accel replacement coils or modules allowed providing it fits in stock location. You are allowed ONE Unaltered 12 Volt Ignition System. Ignition must be out of reach of driver and be accessible for tech inspection all ignition wires must be visible for inspection. One box, One Coil, and One Single Point Distributor. Only Ignition Boxes Allowed Are: MSD 6A p/n 6401, MSD 6ALN p/n 6430, Crane HI-6N Oval track Ignition, p/n 6000-6410, Accel 300+ Ignition w/rev limiter p/n 49300. MSD E-Curve Distributor is not allowed. HEI distributor is allowed. No electronic traction control devices.


ONLY 1 Holly #4412--2 bbl (500 not 750) carburetor will be allowed. Absolutely no alterations or modifications to carburetor, except for removal of choke plate. Choke horn cannot be removed. Altered carburetors will be

CONFISCATED! No transverse mount carburetors allowed. Carburetor must be mounted in conventional manner with float bowl facing forward. Carburetor adapter/spacer allowed, maximum thickness (between carburetor and intake) including gaskets is 1.20 inches.

Top 10 may have to pull carburetor after every feature. Inspection Gauges will be used.

Carburetor may be claimed, following same procedure as shock claim. Driver claiming carburetor may not claim shocks on same night. Claim rule: Carburetor can be claimed for $250 ($250 to driver being claimed). See carb and shock claim rules for claiming details.


Must have 1 inch minimum inspection hole in intake to view camshaft and lifters. No altering intake configuration for an advantage. Only fine tuning will be allowed. Cast iron OEM intakes will be permitted. Must have identification numbers visible. No marine intakes.

Only the following aftermarket intakes are allowed:

**Weiand: X-Celerator Chevy 7547-1, Ford 7515, 7516, Chrysler 7545

**Edelbrock: Torker / Torker II Chevy 5001, 5061, Ford 5021, 5081, 2760, Chrysler 5076

**Edelbrock: Performer Chevy 2101, 2116, Ford 2121, 2181, Chrysler 2176

**Professional Products: Cyclone Chevy 52001, 52007

12. FUEL

Gasoline Only. Racing fuel is allowed. No alcohol, no methanol, no E85 / E98. No performance enhancing or scented additives. Fuel must pass both dielectric and chemical tests. A fuel shut off valve is required on each car. “Fuel Shut Off” securely mounted and easily accessible. The Michigan Dirt Track Inspector has final decision on mounting of shut off valve.

See below for fuel shut off options:

**If running a ball valve: A fuel shut off ball valve is required to be within reach of driver and safety crew and to be mounted with the handle through the deck or firewall not to be mounted inside the cockpit. The valve and handle must be painted bright orange, and clearly labeled with “Fuel Shut Off” securely mounted and easily accessible.

**If running an Oberg Valve: An Oberg Fuel Line Safety Valve is required to be installed under body/deck and behind firewalls, in the fuel line and per manufacture instructions; not to be mounted inside the cockpit. The valve must be securely mounted and easily accessible for inspection. Car must be clearly labeled with "Oberg Fuel Valve" composed of a vinyl sticker (1" stroke orange letters with a white 1/2" outline) sticker must contrast from body and graphics to be easily readable. Two stickers will be required; one on the deck where the ball valve would have been mounted and one on the fuel cell or on the trunk lid.


Mechanical OEM type push rod fuel pumps only. No electric or belt driven fuel pumps allowed.


Fuel cells are mandatory. Tank construction, location and mounting are subject to inspection. A leaking tank is grounds for disqualification. Must have bladder and check valve on fill pipe. Must have canister around tank. Must have approved loop behind the fuel cell, minimum eight (8) inch clearance. Gas cap MUST be secured to fuel cell by cable, chain or tie strap. MUST HAVE ROLLOVER VALVE IN VENT TUBE OF FUEL CELL.


The firewall at the front of the cockpit shall be a wall of protection against a fire from the engine compartment. It shall be tightly solid from top to bottom. Not allowing airflow from the engine compartment to the cockpit. Mandatory: 1/8 inch steel or 1⁄4 inch aluminum plate must be used for drivers’ floor.


Must be Grand National design with upright supports. Must have halo bar. Four door bars are required in the driver’s door. Cage construction should be a minimum of 1 1⁄2" OD seamless DOM tubing (.095). Front and rear hoop must match main cage pipe size. No aluminum tubing. The driver’s seat must be securely fastened at bottom and back of the roll cage, using seat manufacturers’ specifications. Drivers head may not extend above roll cage with helmet on. Must have steel plate 18" x 24" x 1/8" in the driver’s door, must have steel plate 6" x 12" x 1/8" behind the seat in front of the trailing arms.


Any 1968 or newer rear wheel drive American made car is permitted in this class. No station wagons or four-wheel drives. All Pro Stocks will have minimum 102" wheelbase, maximum of one inch difference from right side to left side. All vehicles will be stripped completely of interior, except driver’s seat which will be securely fastened to the roll cage, and will be equipped with a head rest or a high back racing seat and will be subject to local track inspection. The front sub and rear clip may be connected with MINIMUM 2"x2" square tubing or minimum 1 3⁄4” round tubing. All spring and shock mounts must be in stock position.

CAMARO AND FIREBIRD FRONT SUB FRAMES OR UNIBODIED CARS MUST BE 1981 OR OLDER. NO EXCEPTIONS!!! Rear portion on unibody cars, starting at the leaf spring mounts, may be fabricated or reinforced. Stock sub frame may not be shortened or lightened. Frame must be stock from gear box to rear or sub frame. Exceptions are notching for fuel pump and oil pan. Stock frame rails must extend rearward from the front of the gearbox back 40”. Any other modified stock sub frame must add 25 lbs on each side of engine in front of bell housing in the same manner as an aftermarket front sub.


Howe’s part #358-8-01, Phone # 989-435-7080.

Port City # 100-2-205 Ph# 800-472-2464.



Aluminum steering quickener allowed. No rack and pinion steering. Quick disconnect steering wheel required.

Collapsible Steering Shaft Recommended. No Straight Shafts. Must have minimum ONE knuckle in shaft.


NO aluminum suspension pieces (Exception is upper A-Arm cross shaft). Rubber, nylon or steel control arm

bushings only, no offset or bearing type. Welded single-hole shock mounts only. All coil springs must be over 4 1⁄2" in diameter. Front springs must be mounted in stock location. No sway bars. Stock type mounted; steel or aluminum cross shaft tubular upper control arms are permitted. Lower A-Arms must be stock, bolt to OEM frame mounts. Screw jacks are allowed. NO coil over springs. No 5th coils. No coil over eliminator.


NO aluminum suspension pieces. No independent rear suspension. Rubber, nylon or steel control arm bushings only, no offset or bearing type. Single-hole shock mounts only, shocks may be moved, but must remain similar to stock style mounting and location. Rear coil springs must be mounted to rear axle on solid mounts. Springs must be tethered to mount to keep from falling out (Ex: hose clamped or other steel tether).Each rear coil spring may be mounted in front, on top or behind the axle tube as long as the measurement from the centerline of each spring and the centerline of the axle is between zero inches and five and half inches (5 1⁄2”). Bottom control arm mounts on rear end must match side to side. Bottom trailing arm can be no longer than 28” center of mounting bolt to center of mounting bolt and must measure within 2” right to left. All coil springs must be over 4 1⁄2" in diameter. Screw jacks are allowed. All heim joints must be steel, 3⁄4" (minimum). NO coil over springs. NO torque arms or torque links. Steel or composite rear leaf spring allowed. No 5th coils. No coil over eliminator. No swing arm suspension. All brackets must be welded on rear end. Only 3 type of rear suspension allowed, traditional 3 Link (2 trailing arms, 1 pan hard bar, 1 pull bar or lift bar max), traditional Leaf spring rear suspension and stock 4 link suspension.


No (in and out) boxes, all gears must be clutch operated (with motor running and car in still position, driver must be able to engage car in gear and move forward and backward at time of inspection).


Any transmission, manual or automatic. NO quick-change transmissions. Must have scatter shield or protective plate 180 degrees around clutch. If L-plate is used, 1/8” steel plate is minimum thickness that will be allowed. Bert or Brinn type transmissions will be allowed, no ball spline. If running Bert or Brinn type, you must have 50lbs mounted in front of the where the transmission bolts to the bell housing (two 25lb pieces). Drive Train must be disengage-able. NO direct drive systems.


Magnetic Steel drive shaft only, must be painted white and have a steel drive shaft loop measuring 1/4” thick by 2 inches wide, located on the forward 1/3 to prevent it from dropping onto the track.


Any steel approved OEM passenger car or truck non-cambered rear end (housing and carrier) allowed. Safety hubs (floater) allowed. All components must be steel, exceptions are: lowering blocks, axle cap, and drive flange may be aluminum. No adjustable lowering blocks. One inch inspection hole in housing required. Full steel spool, steel mini spool or welded rear end only. Steel axles only. No quick change devices. One piece drive flange only. No torque-dividing differentials. No Gold Tracks. No Lockers. No scalloped ring gears.


Stock four wheel hydraulic brakes. All must be in working condition. Neal type brake pedal assembly permitted. Single piston, steel calipers only. Brake caliper must be unaltered. No shut off valves. No ratchet valves. No Left to Right proportioning allowed. One Front to Rear proportioning device (brake adjuster) allowed. No pinched off brake lines. All Brake lines must be visible.


Eight (8) inch maximum, racing wheels and 1 inch racing / safety lug nuts required for all wheels. NO Wide 5s allowed. Bead Lock Wheel allowed on Right Rear Only, if running bead lock, right rear tire must have at least 17 pounds of air after race. Magnetic steel wheels only, no plastic or carbon fiber wheels allowed.


One shock absorber allowed per wheel. No air coil-over or struts allowed on the front. Steel racing shocks are allowed on the front and rear. One 90/10 shock allowed, mounted from top of rear end housing to roll cage. No bump stops. No external adjustable shocks.


$50.00 per shock, may claim any or all shocks, 1 claim PER DRIVER, PER SEASON. Driver that finishes feature on the lead lap may claim anyone in the top 4. You must make claim in claiming area immediately following the feature with money in hand. FAILURE TO SELL: disqualified for the night, loss of points and money for that night only and must qualify from rear most spot the following week. This is intended to keep the cost of this class down. See carb and shock claim rules for claiming details.


American Racer P245/70D-15 tires only. Tire must have MSPA stamp. No Hoosiers, no McCreary. You may groove, sipe and/or grind tires. Chemical alterations, vulcanizing, tire softening, defacing and/or altering the face of the tire lettering and/or tire stamping will not be permitted. Chemicals or tire softening is not permitted at any time. Tires will be subject to a durometer test. Your tires must be harder that the baseline determined by MICHIGAN DIRT TRACK officials. Tires may be inspected at any time. Tire pressure must be at least 17 lbs on right rear if running bead lock wheel, after each race.


No radios, EXCEPT MANDATORY RACECEIVERS, allowed in car, or with any pit member or anyone connected with the racecar.


3,000 lbs minimum. Added weight MUST be in plain sight, painted white or silver, MUST have the car number painted on it in a contrasting color and must be readable. No cement pellet or liquid style weights. Weights must be securely mounted to the car with the minimum of two 1⁄2" bolts and nuts per 50 pounds of weight. Loss of any weights may be grounds for disqualification. No weight on rear bumper or outside body of the car.


MANDATORY – FRONT AND REAR. Chains must be used; cables are not acceptable tow hooks. Chain must be a minimum of 3/16”. Tow hook cannot extend in front of car. Both must be easily accessible. If there are no wrecker hooks on the car, it will be pushed, towed, or dragged to the infield until after the racing program is completed. NEITHER WRECKER CREWS NOR RACETRACK PERSONNEL WILL BE RESPONSIBLE FOR ANY DAMAGE DONE TO THE ANY VEHICLE.


Claiming driver must run claimed carb/shock(s) the next 2 times the driver and/or car is at the same track where the carb/shock(s) was claimed. This must be completed within the next 4 scheduled events at the track the engine was claimed from or refusal penalty will be assessed. (This excludes rainouts, but is not limited to calendar years.)

Refer to general rules for all claiming procedures.

First four (4) position finishers in the feature event must report directly to the claim area and are subject to

carb/shock(s) claim by any driver finishing fifth (5th) on back. Any driver lapped by the fourth (4th) place car is not eligible to claim. Drivers are allowed to claim only one carb/shock(s) per event, regardless of the outcome of that claim. In case of multiple claims on the same carb/shock(s), carb/shock(s) will go to the claiming driver’s number pulled from a drawing.

Drivers making the claim must drive his/her car immediately after the finish of the feature, (under its own power) directly to the claiming area. Only drivers and officials are allowed in the claiming area. Claims must be made within five (5) minutes of the end of the feature and claimed carb/shock(s) must be completely removed within one hour from the time the claim is made and driver agrees to sell the claimed carb/shocks(s). First sell or no sell by driver being claimed is binding. Promoter may claim any carb/shock(s) following the feature; so long as claim is made within the five (5) minutes of allotted time.

REFUSAL to sell will forfeit all cash and contingency winnings for feature, any trophy earned in feature, ALL SEASON POINTS and awards, driver will also be suspended for 30 days and will have to pay $1,000 fine before racing in the Pro Stock class again and cannot make a claim at the track the refusal took place for one calendar year. Any driver found to be claiming of carb/shock(s) for anyone else other than himself/herself will lose all points for the season and will be suspended for 30 calendar days. All claimed carbs/shock(s) must be removed from car at track; buyer must examine carb/shock(s) before removal. Once removal has started, sale is final.

NOTE: Driver may only make one claim on claimable items per night. If Driver makes Shock(s) Claim then Driver cannot claim Carburetor. If Driver makes Carburetor Claim then driver cannot claim Shock(s).

NOTE: Driver may only make one Carburetor Claim and one Shock(s) Claim per season. Unless that driver has had 2 claims made against them. Then that driver may make one additional claim.

NOTE: Claiming driver must have raced the two weeks prior to claiming.

NOTE: Your race car must be legal to make a claim.

Officials have final discretion on the rules. It is always best to ask beforehand than to assume.