Fri nights: Gates open at 5 PM, racing starts at 7:45 PM   |   4658 E River Rd, Mt Pleasant, MI 48858    |   989-773-2387

Hobby Stock Rules


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.

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



Rules apply at all times car is on track. An operational 2-½ 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 or SA2010 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. 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.


Any American OEM full body rear wheel drive passenger car, 1964 or newer, full frame or unibody. Minimum 107.5 inch wheelbase, maximum one inch difference from side to side. Rear of frame behind rear tires, no further forward than one inch behind factory seam, may be replaced in OEM location with minimum 2 inch by 2 inch steel tubing with 0.095 inch wall thickness. Factory seam must remain visible. Unibody cars must tie rear frame to front frame. Frame may be “X” braced. No mixing of frame and / or suspension parts. Engine and Body must match. May use Ford frame with GM engine and body or Chrysler engine and body. May use GM frame with Ford engine and body or Chrysler engine and body. May use Chrysler frame with GM engine and body or Ford engine and body. 1981 or older Camaro allowed.


Main cage must consist of continuous hoops, minimum 1.5 inch O.D. seamless DOM tubing, with a minimum wall thickness of 0.095, low carbon or mild steel recommended. Four-post roll cage required, front down bars and rear hoop must be welded to OEM frame. Driver’s head must not protrude outside cage with helmet on. Rear hoop must have “X” brace, consisting of one full horizontal and one full diagonal bar, minimum 1.25 inch O.D. with 0.083 inch wall thickness. Front down bars must be tied together; passenger side front down bars may be maximum 11 inches in from top of door. Must be minimum 40 inches between outside edge of front and rear down bars at top of door panel. Maximum 41 inches (48 inches for 1988-1996 GM bodies) from top center of windshield to front edge of rear hoop. Maximum 13 inches (20 inches for 1988-1996 GM bodies) to front edge of top halo. Top halo must be minimum 40 inches across, outside to outside. Rear hoop may be maximum 12 inches in from bottom of opera window. Minimum one cross bar in top halo. May have maximum two horizontal bars, (in addition to bar tying front frame horns together) for radiator protection; must be behind bumper, within confines of body, no wider than stock frame horns. Required rear kickers (down bars) and engine hoop must be minimum 1.25 inch OD tubing, with 0.083 inch wall thickness. Fuel cell protection required must be mounted frame rail to frame rail, no higher than fuel cell, inside trunk area with maximum 1.75 inch OD tubing. All bars must be inside body. Foot protection bar required.


All door bars and uprights must be minimum 1.50 inch O.D. with 0.095 inch wall thickness. Minimum three door bars, both sides, parallel to ground, and perpendicular to driver. Minimum four uprights tied from frame to top door bar on driver side, and minimum three uprights on passenger side. Steel door plates, 18 gauge or 0.049 inch minimum thickness, must be securely welded to outside of door bars on driver’s side. Plate must cover area from top door bar to frame and from rear down post to five inches in front of seat. Must be visible for inspection.


Unaltered OEM, and centered over wheel wells (front to rear and side to side). Body and engine make must match. Front body mounts must be visible. Sunroofs and T-tops must be enclosed. OEM or aftermarket plastic nose and tail pieces allowed, must match body. All body panels may be gutted, including fenders, doors, hood, roof, quarters and trunk, but must remain original size. Roof Rake must remain similar to stock for make and model of body. Roof Rake should be parallel to body. Roof cannot be altered to create a wedge for down force. Hood must be separate from fenders, in OEM location, with rear sealed off from driver compartment with metal. All inner wheel wells may be removed. Rear edge of trunk may be trimmed and rear tail light support removed only if aftermarket tail piece is used. Trunk floor must be removed over rear end housing; entire trunk floor may be removed. All windows must remain open, except opera windows may be covered with clear lexan, no decals. All ‘B’ pillars may be trimmed to minimum 2 inch width, must remain within OEM location. Maximum seven inch metal sun visor may be added to top of windshield opening. Wheel wells may be trimmed for tire clearance. No spoilers, hood scoops or reflective body panels. Rocker skirt/flare allowed between tires only, cannot extend outside tires, minimum 4 inch ground clearance. Allowing fiberglass hoods, roofs, trunks.


Minimum of three windshield bars in front of driver. Aluminum high-back seat only, must be bolted in using minimum 0.375 inch bolts and follow manufacturers installation and usage guidelines. Seat must remain inside all confines of roll cage. Every part of the seat must be at least 30" in front of center line of rear axle. Driver must be sealed off from track, driveline, engine and fuel cell. Kick and rocker panels may be removed. Front OEM firewall may be replaced using steel fabricated firewall, 18 gauge or minimum 0.049 inch thickness. Top of firewall can be no further back than 12 inches from the back of engine block, measured horizontally. Bottom of firewall can be no further back than rear of oval body mount frame hole. Dash must not extend more than 24 inches back from top of firewall. Dash must be flat, rear can be no higher than front, except for cowl in front of driver. OEM floor pan may be replaced using steel fabricated floor pan, 18 gauge or minimum 0.049 inch thickness, securely welded to frame. Floor pan may be replaced from front firewall to rear halo supports. Must remain flat/OEM appearing from frame rail to frame rail, can be no higher or lower than frame rail. Exception is maximum 8-inch tall drive shaft tunnel. Tunnel must remain similar to OEM tunnel in size. No cockpits, interior must remain open. Rear firewall may be aluminum or steel and may be located no further forward than rear halo supports and no higher than bottom of rear opera windows. All holes in firewalls must be covered with metal. No driver-adjustable devices allowed. No brake adjusters. No mirrors.


All components and mounts must be steel, unaltered OEM, in OEM location and match frame. Rubber, nylon or steel lower A-frame bushings only – no offset or bearing type. No sway bars. Exceptions are: OEM upper A-frame mount may be moved or replaced with aftermarket steel non-adjustable mount matching upper A-frame bolt on design; OEM or OEM replacement ball joints allowed. OEM upper A-frame may be replaced using steel non-adjustable aftermarket upper A-frame. Front weight jacks allowed.


No rack and pinion. All components must be steel, unaltered OEM, in OEM location and match frame. Exceptions are: bolt on spindle savers allowed, OEM steering column may be replaced with steel knuckles and steel steering shafts (collapsible recommended). No Straight Steering Shafts Allowed (Must have minimum ONE knuckle in shaft). Quick release required – steering quickener and steering wheel may be aluminum.


One steel nonadjustable unaltered shock per wheel. No coil over, air, or remote reservoir shocks. No Schrader or bladder type valve allowed. No coil over eliminators. One or all shocks may be claimed per event for $50 each, counting as one claim on card, following shock claim procedures. If driver claims shocks driver cannot claim engine or carburetor that night. Outboard shocks on front only allowed.


One steel spring per wheel only. All coil springs must be minimum 4.5 inches O.D. and non-progressive.


All components and mounts must be steel, unaltered OEM, in OEM location, and match frame. No independent rear suspension. Rubber, nylon or steel control arm bushings only, no offset or bearing type. Welded single-hole shock mounts only. Exceptions are: coil springs may be moved, but center line of axle tube can be no further forward than the front of spring, or no further back than rear of spring; shocks may be moved, but must remain similar to stock style mounting and location. Upper and lower control arm mounts on rear end must be level with each other. Only one hole per mount. Screw jacks on rear allowed.


Any steel, approved OEM passenger car or truck non-cambered rear end (housing and carrier) allowed. Safety hubs (floater) allowed. No sway/panhard bars. 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.


Maximum one inch wide by two inch tall steel or lexan rub rails allowed – bolted flush to body. Front and rear tow hooks mandatory. All front bumpers must be mounted minimum six inches from front frame horns. Steel bumper mounts only. No sharp edges allowed on bumpers, rub rails or bolts. One of two bumper options must be used and must be OEM height:

OEM: Bumpers not covered by plastic nose or tail piece must be complete, unaltered OEM, capped to fender with steel, welded or bolted. No bars past outside edge of body other than rub rails.

Aftermarket: Fabricated tubular bumpers allowed, but must be covered by plastic nose or tail piece and bent to fit with rounded ends. Main bumper bar must be minimum 1.5 inch O.D. (maximum two inch) with 0.083 inch (maximum 0.125 inch) wall thickness on front, and 1.75 inch O.D. with 0.120 inch wall thickness on rear.


The only racing type tire that is allowed is the American Racer P245/70D-15 Tire with MSPA stamp on sidewall. No altering, chemical softening or conditioning of tires. Tires may be ground grooved and sipped.No Hoosiers, No McCreary. STREET TIRES OK MUST BE SAME SIZE AS AMERICAN RACER


Wheel spacer or offset wheel, or a combination of the two allowed, but combination cannot result in wheel offset being wider than standard 2 inch offset wheel, for each wheel. Rule is intended to prevent widening of tire track / stance. Example: if using 3 inch offset wheel, a maximum 1 inch wheel spacer would be allowed, which would result in same overall offset as a 2 inch offset wheel. Maximum 8 inch wide wheel. Racing wheels and racing / safety 1 inch lug nuts required on all wheels. May use bead lock, on right rear only. If using bead lock, right rear must measure 17 psi after each race. External, steel bead lock only and it cannot make wheel any narrower than 8 inches and no wider than 8.75 inches. Steel bolts only. No Mud plugs or wheel covers in Street Stock Class. No bleeder valves.


Steel, unaltered OEM, or unaltered OEM replacement, operative four wheel, drum or disc brakes allowed. Front components must match frame and maintain minimum OEM dimensions for hubs/rotors and calipers, cannot be lightened. OEM diameter caliper pistons only. Bolt pattern may be changed. Larger studs allowed. Vented rotors only, no scalloped or ceramic coated rotors. Rear rotors may be aftermarket 0.810 inch thick (new). No floating brakes. No brake shut-off, no ratchet valves, no pressure sensitive devices. No left to right proportioning allowed. Front to rear brake bias adjustment cannot be made from driver’s compartment or while in competition. No pinched off brake lines. Brake lines must be visible. Aftermarket pedal assembly allowed.


May run stock exhaust manifolds or round tube headers only. All primary header tubes must enter directly into one collector at same point at end of header. Must remain dual exhaust, no crossover or “Y” pipes. No exhaust through body panels or fenders. No merge collectors. No exhaust sensors. Must point away from track and driver and exit behind driver compartment. Holes in exhaust pipe will not be allowed, no drilling of pipe and connections must be tight and leak free. Schoenfeld muffler, IMCA 609 or Schoenfeld racing muffler.


Mechanical OEM type push rod fuel pumps only. Racing fuel cell required, must be in minimum 20 gauge steel container. Must be securely fastened in trunk above top of rear frame rails, behind rear tires, no further forward than factory seam where rear frame rail can be replaced, with minimum two solid steel straps around entire cell, two inches wide and 0.125 inch thick. No fuel cells allowed over rear end housing. Metal firewall must be between driver and fuel cell. All cell mounts must be steel, securely welded to frame/cage. No adjustable fuel cell mounts. Fuel cell vents, including cap vent, must have check valves. If fuel cell does not have aircraft style positive seal filler neck/cap system – a flapper, spring or ball type filler rollover valve is required. Fuel cell cap must be secured to fuel cell by cable, chain, or tie strap. Fuel lines through driver compartment must run through metal pipe or metal conduit. One fuel filter only, cannot be in driver’s compartment. No cool cans. Air cleaner top/stud cannot direct air into carburetor. No top flow air cleaner housings, cold air boxes or air cleaner duct work.



Stock 2 barrel carburetor allowed, must match make and manufacturer of car. Example : Ford-to-Ford, Chevy-to-Chevy, Mopar-to-Mopar. Holly #4412–2 bbl (500 not 750) carburetor will be allowed. Air bleeds cannot be removed. Float bowl must face forward. No transverse mount carburetors. 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 engine claim. Driver claiming carburetor may not claim engine or shocks on same night. Claim rule: Carburetor can be claimed for $300 THAT’S THE PRICE AT THE PARTS STORE FOR STOCK. Engine claim provisions will prevail. Carburetor is not included with engine claim.

19. FUEL

Gasoline Only. Racing fuel is allowed. No alcohol, no methanol,  No performance enhancing or scented additives. Fuel must pass both dielectric and chemical tests.


One 12 volt battery only, must be securely mounted between frame rails, and positive terminal must be covered. Battery must be in Marine type case if mounted in driver compartment. Starter must bolt in OEM location. Car must have capability of starting without being pushed or pulled. Car must leave initial staging area on demand, unaided, or go to rear of that race.

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.


No unapproved cameras, transmitting or listening devices. No timing retard controls, or digital gauges (including tach). No electronic monitoring computer devices capable of storing or transmitting information except analog tach. No adjustable ignition control boxes. Only one OEM 12 volt ignition system allowed, must be out of driver’s reach. No additional ignition accessories. No magnetos or crank triggers. No MSD, Accel or Crane (Aftermarket) ignition boxes allowed. OEM type alternator with internal regulator allowed. No electronic traction control devices.


Must have at least two forward gears and one reverse, plus neutral position. With motor running and car in still position, must be able to engage car in gear and move forward, then backward. Only OEM production type transmissions allowed – two speed, three speed, four speed and automatic. No five speed (or more) transmissions, no “in and out” boxes, no Bert / Brinn style transmissions or quick change devices allowed. Functioning shift levers must be in OEM location. Flywheel / flexplate must be bolted directly to end of crankshaft, and pressure plate must be bolted directly to flywheel / flexplate. One flywheel / flexplate only, and all driveline components within bellhousing must rotate consistent with engine RPM while car is in any gear. Unaltered flexplate must be full OEM, or OEM replacement.

Manual: Must be OEM or OEM replacement case and have a working  clutch inside explosion-proof steel bellhousing – minimum 270 degrees around top of clutch/flywheel area.


Automatic: Must remain in OEM or OEM replacement case, with a functioning OEM appearing pump. Aluminum OEM bellhousing may be replaced with aftermarket explosion-proof aluminum bellhousing. Original OEM bellhousing must have approved scattershield constructed of minimum 0.125 inch by three inch steel, 270 degrees around flexplate. Manual bump starts allowed.

Drive Shaft: Minimum two inch diameter magnetic steel drive shaft must be painted white. Magnetic steel slip-yokes only. 360-degree drive shaft loop required and must be constructed of at least 0.25 inch by 2 inch steel, or 1 inch tubing, mounted 6 inches back from front U-joint.


The forward most spark plug hole may not be set back any further than a perpendicular line with the center of the upper ball joint for each manufacturer. Aftermarket engine mounts allowed, including mid-plate. Engine must be OEM appearing, must be able to be used in conventional passenger car without alteration. GM engine with GM body, Ford engine with Ford body, Chrysler engine with Chrysler body. Radiator must be mounted in front of engine. Cooling system may be modified. No antifreeze allowed, water only. Overflow tubes must be directed into overflow tank (one gallon size recommended).


Any American make engine allowed. Steel heads, block and oil pan only. OEM passenger vehicle production block only. No GM Bowtie, Ford SVO or Chrysler W blocks. Castings and fittings cannot be changed, no machine work on outside of engine. No cubic inch limit. Full roller rocker arms allowed. Must have 1 inch inspection hole in intake to view camshaft and lifters. No

stud girdles. Flat tappet cam/lifters only, cannot alter lifter bores. No mushroom lifters. No roller cams. OEM firing order cannot be changed (GM: 1-8-4-3-6-5-7-2). Steel or aluminum water pumps allowed. No electric water pumps allowed. ‘Wet’ sump oiling system only. Accumulator allowed – cannot be located between seat and door bars.


Must have 1 inch minimum inspection hole in intake to view camshaft and lifters.

Unaltered, aluminum or cast iron, low rise, two- or four-barrel intake. No porting, polishing, shaving, or grinding allowed to any intake. Rise of stock intake above engine block can be a maximum of 4.00 Inches. To figure intake rise height, add “A” + “B” and divide by 2. Example A is 3.7”, B is 4.1”. (3.7+4.1) / 2 = Intake Rise Height of 3.9”

Cooling lines allowed on aluminum intakes. Disqualification, loss of points, purse and if any alterations are found to intake. No marine, no bow tie, no air gap and no high rise intakes.


$1,000 CASH claim on engine, flywheel and balancing plates. Driver being claimed has the option of taking $500 and other drivers motor. Driver making the claim must pay an additional $50 to the wrecker. Driver making the claim - his car cannot be leaking fluid, overheating, or smoking.

Claiming driver must run claimed engine the next 2 times the driver and/or car is at the same track where the engine was claimed. Even if it takes 2 weeks, 2 years, etc. to fulfill the 2 time requirement or may not compete at Mt Pleasant Speedway  in the Street Stock class again for the remainder of the season

(B) Claim does not include – 1. clutch, 2. pressure plate, 3. bellhousing, 4. exhaust manifold or headers, 5. carburetor, 6. starter, 7. motor mounts, 8. oil/temp. sending units, 9. carburetor spacer, 10. fan and pulleys, 11. clutch ball, 12. clutch arm, 13. throw out bearing, 14. dip stick, 15. water pump, 16. fuel pump, rod and plate, 17. distributor, 18. plug wires, 19. water outlet and restrictor, 20. breathers.

First four (3) position finishers in the feature event must report directly to the claim area and are subject to engine claim by any driver finishing fifth (4th) on back. Any driver lapped by the fourth (4th) place car is not eligible to claim. Drivers are allowed to claim only one engine per event, regardless of the outcome of that claim. In case of multiple claims on the same engine, engine 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 engines must be completely removed within one (1) hour from the time the claim is made and driver agrees to sell the claimed engine. First sell or no sell by driver being claimed is binding. Promoter may claim any engine 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, and ALL SEASON POINTS, driver will also be suspended for two weeks and may not race in the Street Stock class for the remainder of the season. Any driver found to be claiming an engine for anyone else other than himself/herself will lose all points for the season and will be suspended for 30 calendar days. All claimed engines must be removed from car at track; buyer must examine engine 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 or Engine. If Driver makes Carburetor Claim then driver cannot claim Shock(s) or Engine. If Driver makes Engine Claim then Driver cannot claim Shock(s) or Carburetor.

NOTE: Driver may only make one Engine Claim and 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 engine claim.


Minimum weight limit is 2800 pounds, after race with driver in car. No cement pellet or liquid style weights. No tolerance. No weights and/or loose objects in driver compartment or outside body and must not be visible. Weights must be securely mounted to frame or roll cage and painted white with car number on it. Weights must be attached with at least two 0.5 inch bolts. Cannot have more than 25 pounds of ballast weight per 0.5 inch bolt. Example: 75 pound stack of weights requires three (3) 0.5 inch bolts. No titanium, magnesium or carbon fiber products. No gun-drilled, tubular, hollow bolts or studs. Must use magnetic steel fasteners only.


Both must be accessible. If no wrecker hooks are on the car, the car will be pushed, towed, or dragged to the infield until after the racing program is completed.


NOTE: Non-Conforming or altered parts may be confiscated

No reflective car numbers. If we can’t see them from 100 feet away at 80 MPH, you may not be scored.