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2015 Street Stock

2015 Street Stock Rules


American made passenger cars only.  Minimum of 108 inch wheelbase.  Any measurement less than 107.5 inch will be considered illegal. Wheel base may not be altered to change the original wheelbase.  Chevrolet Monte Carlo, Buick Regal, Olds Cutlass, Pontiac Grand Prix, and Novas will be allowed.  Camaros must be 1981 or earlier.  Camaro on Camaro Frame Only. All bodies must be steel or aluminum factory appearing.  Any steel factory style OEM body is permitted, and must have factory steel roof and window post.  Hood, trunk, fenders, doors, and quarter panels may be steel or aluminum but must maintain factory body lines. No late model style bodies.  Note:1981-1988 Performance Bodies street stock Monte Carlo (steel body), Five Star racecar body package 601-101S, Performance body 2000 Monte Carlo (steel only) and 1981 Camaro part # PBO18X001 (must have stock steel and roof and window post) are the only after-market bodies allowed. All bodies must be proportionate to the year and make of frame. Frame must remain square and to factory specs.  Interchange of non-stock packages will be closely scrutinized and subject to track official approval. Firewalls must be complete, from fender to fender, top to bottom.  Firewall cannot be further back than 40 inches from top (front) of sector bolts in frame. Cut area must be closed with 20 ga. steel or aluminum.  Stock or steel floor pan must extend from front firewall to rear firewall.  If decking is installed in driver’s compartment must be enclosed with 20 ga. steel, with complete interior window level decking (may be aluminum).  If compartment enclosed, and decking in place, rear firewall may be removed. Floor pan must remain from front firewall to no less than 25 inches forward of rear axle centerline and must fully extend from left rocker panel to right rocker panel. Driver must be on left side of drive shaft.  Driver must have an unobstructed view at all times.  B pillar must remain but can be replaced with plastic or aluminum, in stock location.  No narrowing of frame allowed.  Frame may be altered only forward of steering gear box. On the rear, frame may be altered no less than 8” behind original upper shock mount. Inner fender well may be altered or removed.  Rear bottom of driver’s seat no less than 30” forward of left rear axle centerline.


Ballast allowed, must be welded or bolted to the frame or roll cage structure with a minimum of two ½” bolts per 100 lbs. Minimum of two (2) bolts per piece/location.  Bolted ballast must be painted white and car number must be on ballast.  NO liquid ballast. 


WEIGHT: 3150 lbs. Minimum with driver after heat and feature event. 3000 lbs for crate motor with driver after heat and feature event



Maximum of 364 cubic inches Ford, Dodge, and GM are allowed.  Engine displacement formula for determining cubic inches is: bore x bore x .7854 x stroke x number of cylinders = cubic displacement. Any engine exceeding maximum allowable cubic inch displacement limit will cause disqualification.  Only cast iron OEM production blocks allowed. NO bowtie, Dart, Little M., ect. GM chassis – GM block, Ford chassis – Ford block, Dodge chassis – Dodge block ANY cast or steel crankshaft allowed.  After market fluid dampeners allowed.  ANY steel connecting rod allowed. Aluminum rods PROHIBITED.  Pistons may be flat top (2) valve relief or OEM equivalent. NO domed pistons! Cast or forged OK. Any type pistons rings allowed. Must have a minimum of (2) compression rings and (2) oil ring. Floating wrist pins are allowed. NO titanium. Engine block permitted a minimum of .0 deck clearance. Piston must not hit straight edge held over cylinder while engine is cranked with starter. Any camshaft: solid or hydraulic. NO rollers or mushrooms. NO oversize lifters. NO dry sump oil systems or vacuum pumps.

An illegal engine consists of any illegal parts found horizontally from the fan blade through the flywheel and vertically from the oil pan through the carburetor.


CRATE ENGINE: Must use unaltered sealed GM #88958602 or #19258602 crate engine.  Upon inspection, any different, altered or mission GM seal bolts will result in disqualification.  GM seal bolt exception is IMCA approved and issued cable-lock rebuild system and oil pan my be replaced by IMCA certified builder with Kevko pan #1090NRH2/ISP and Kevko pick-up#1003-3/4.  Must run Holly 4412 2 bbl or Holly stock 650 4 bbl that passes go/nogo gauge. 




Note: Casting numbers must remain in cylinder head or head is illegal. Retains to manufacturer, part # and intake port runner size. Also, NO o-ringing of block to mate head gasket with block and head.
Any 23 degree heads cast iron ONLY. NO more than 200cc on intake runners.2.02 intakes and 1.60 exhaust valves maximum.
NO acid dipping, porting or polishing. Heads maybe flat or angle milled.
Screw in studs, pinning and guide plate allowed. NO titanium, valves or components.
Any work done in the bowl area must be done with a 360 degree cut, with the valve guide as the center point. Full rocker arms are allowed. Roller tip rocker arms are allowed. Polylocks are allowed. Stud girdles are allowed.  NO Jessel or similar allowed.
NO aluminum or titanium is allowed. Any breather/valve cover combination is allowed.



Minimum engine height is 10” from the ground to the center of the crankshaft. This will be measured on the front of the crankshaft/pulley.

ENGINE SETBACK is #1 spark plug even with ball joint or forward.
Side engine mounts may be 45 degree style, steel ONLY. Rear motor plates allowed.


No fuel injection.  GM, Ford, Dodge must run Holley 4412, HP 4412 silver or black 2 bbl. No modifications or machine work allowed except chock horn may be milled off on 4412. Gasoline or racing fuel allowed. No alcohol. Carb spacers/adapters allowed. Must NOT exceed 1¼” in thickness. NO injectors or pressure systems allowed. Any cast iron or aluminum intake manifold allowed. Note: No Brezensinki or special order intake allowed. NO tin intakes. NO tunnel rams. Any brand / style / size of air cleaner are allowed, but no kind of RAM air. NO coating, NO acid porting, NO porting, polishing or port machine or intake manifolds, intake manifold may not be altered in anyway. NO vacuum leaks between the intake valve and the top of the carburetor.  Tech Official’s may use any inspection procedure, including Test Gauges. Holly 4412, HP 4412 silver or black 2bbl must pass go/no go gauge.



Stock or replacement ignitions ONLY. HEI must remain in one unit. MSD or any module may be used as long as it fits inside the cap with no alterations. Vacuum advance may be removed and the pick-up coil locked. Must be stock appearing housing and cap.  MSD Boxes (6A, 6AL, 6T ONLY) are allowed.  NO crank triggers or magnetos.



Cast iron exhaust manifold is allowed. Street headers are allowed and Schoenfeld headers are allowed. Maximum 3½ OD. No zoomy or 180 degree over the top of engine exhaust allowed Header must be under chassis style, exhaust must run past the front edge of the Driver seat or outside of the car.



Only one (1) radiator is allowed. Radiator must be mounted in the stock location.
Radiator may be aluminum. Racing radiator cap is allowed. Must mount radiator overflow through the frame and exit the frame under the car just behind the right front wheel.  NO electric cooling fans.






NO electric fuel pumps.  ONLY stock mount push rod activated pumps are allowed.
Holley and Carter style are allowed.



Maximum 22 gallon fuel cell. Must be in can.  Fuel cells ONLY. Must be securely mounted inside trunk area ONLY, must be between frame rails and must be totally enclosed from the driver compartment. A minimum of two (2) fuel cell straps 2” x ⅛” required to secure fuel cell. Fuel cell with a rollover valve is required. Fuel cell protection bar is required. Must be a minimum of 1½” x .095”. It must protect the fuel cell from the rear. It must be as low as the fuel cell, and extend from side to side as wide as the fuel cell. It is recommended that this bar be attached to the frame, NOT the bumper. If the fuel cell protection is not present the car will NOT Be allowed to continue racing. The fuel cell protection bar must be attached to the frame.



Any powerglide/350 turbo/3 or 4 speed aluminum or steel or Brinn transmission. All forward and reverse gears must be in working order, except Powerglide.  Powerglide is allowed either or both forward gears, with neutral and reverse in working order. Standard transmissions must have all gears working. Can run any clutch/flywheel/torque converter/direct drives/valve pump. All standards must have bell housing made of ¼” thick steel and cover 180 degrees over the sides and top of the clutch assembly. Quick-change transmissions or transmission adapters for gear change are NOT allowed. Car must be self-starting and having working neutral, reverse and forward. Transmission coolers are allowed. If exposed to driver, it must be shielded in case of leaks. Automatic Transmissions must have a scatter shield, minimum 3/16” x 4” wide steel. May be attached to the bell housing or the floor pan.




Driveshaft must be steel, and must be painted white. Must have a steel driveshaft loop (360 degree) connected to the frame within 6” of the front driveshaft u-joint. Minimum of 2” x ¼” or minimum of 1” round. NO chain loops allowed as front loops.



After-market axles, studs, and mini-spools are allowed. NO posi-trac, or limited slip style rear ends. Rear end axles must be locked together. 9” Ford allowed. Any gear ratio may be used if no alteration to housing is required. Bolt pattern on the axle / drums may be changed. Wheel adapters are allowed. Rear end may be locked by welding spider gears, using a mini-spool or with a full spool. NO aluminum. NO quick change rear ends. Floater rear ends Ok. Disc brakes are allowed. Steel components ONLY. Single piston ONLY.



All components at wheel must be stock OEM. Except disc must be steel. Dual master cylinder after market brake pedal is allowed. Rear brakes may be disc. An adjustable proportioning valve or crank adjustable front to rear break bias may be used. Minimum of three (3) working brakes is required. If using (4) brakes a shut off valve may be used for the fourth brake. If using three (3) brakes, the fourth brake assembly need not be present. If the fourth is the right front, the caliper and the rotor may be removed. Spindle to remain unaltered. Cooling holes may not be drilled in any brake component.



Quick release steering wheel is mandatory. Quick steer is optional. NO chains or sprockets are allowed in the steering system. D & M OK. Steering left of drive train ONLY. Bump steer cannot be adjusted. Center link, inner tie-rods, outer tie-rods or sleeves cannot be altered. Power steering is allowed. After market power steering may be used. NO rack and pinion steering. Stock OEM steering box must be used.



Upper control arm brackets may be moved for caster and camber adjustment. Must use stock OEM upper control arms or steel tubular non-adjustable control arms. Mounting brackets may be stock or approved aftermarket weld-on upper control arm mount for use with tubular upper control arm,  3/8” thick steel with 6” bolt center. Upper and lower control arm bushings may be after market. Steel bushings are allowed front and rear. Lower control arms and brackets must be stock OEM.  Uppers and lowers must match make, model and year of frame. If used, sway bars and brackets must remain stock. Racing springs are allowed. Adjustable spring buckets are allowed. Jack bolts are allowed Spindles and rotors must remain stock for year, make and model. Spindle may be reamed for bigger ball joints. NO grinding or lightened parts. ⅝” studs are allowed in any bolt patterns. Tie-rods, center link pitman arm, steering box and idler arms must be stock for year, make and model. Larger size press-in ball joints may be used. NO mono-ball joints allowed. May be welded. If rear coil spring car, lower rear end trailing arm brackets maybe moved for pinion adjustment. Metric cars must retain all four (4) links, and must match year, make and model (OEM). NO suspension parts may be altered or lightened on leaf spring cars. Must remain stock for year, make and model of car. Must be Ford on Ford, GM on GM, Dodge on Dodge. No After-Market suspension parts, such as panhard bars, j-bars, hard bars, pull-bars, etc.  Ford 9” rear end is allowed on any make and model. Wheel adapters are allowed with 5/8 studs. Non-Adjustable lowering blocks allowed, two (2”) inches max. Sliders or shackles on leaf springs maybe adjustable. After market steel leaf and coil springs are allowed. Composite leaf springs allowed on Cameros and Novas. NO coil overs.  Rear coil springs ONLY.  May use maximum 2” inch spacer welded to frame or rear housing. Adjustable coil spring spacers allowed, front and rear. Aluminum suspension parts are NOT allowed, even if it fits year, make and model.



Shocks must be steel, may be after market. Front & Rear: any steel shock, and may be relocated. One shock per wheel. NO more than four (4) shocks on car.



Roll cage material must be a minimum of 1½” x .095 wall thickness round steel tubing. Must be box type cage, four (4) uprights connecting tubing on roll cage. Roll cage must have rear supports going down to the frame and may extend into the trunk area, and diagonal tubing is required to keep the cage from moving from side to side. Roll cage must have minimum three (3) door bars ( 1½” x .095). The center of the roll cage and driver's seat may be no further back than the third (3rd) body mount bushing frame hole for metric frames. All welds must be complete and pass safety inspection by tech personnel.  NO iron or square tubing allowed in main section of the cage.  NO brazing or soldering.  NO aluminum cages allowed. A minimum of two (2) bars, (engine bay bars) one (1) per side, may extend from the main roll cage to points on the main frame in front of the upper control arms, These bars may have three (3) additional braces per side to the main frame. A minimum of two (2) bars may extend to rear of main frame from the main cage. X-bracing is allowed, including frame to frame under the driver. Driver’s head must NOT protrude outside of the cage with helmet on. Cutting of the floor is limited to cage placement and / or sub-frame connectors. Replacement must be made with a minimum of 20 gauge steel.





Hoods and trunk lid must have quick release system (hood pins). Hole may be cut in hood for air cleaner. Air cleaner cannot extend more than four (4”) inches above hood. Hood scoops allowed.  Hood must set flat on the deck, firewall or the dash and provide a seal.



One single nerf bar between the front and the rear wheels, on each side of the car is allowed. Maximum size 1½” x0.95”. This may be rectangular tubing, a maximum of 2” x1”. They are to be attached to the cage at the front and rear sections of the nerf bar. Maximum of two (2) supports allowed for the nerf bar. NO center supports are allowed on the nerf bar.  Must have rounded or tapered ends on front. NO sharp edges or corners. The rear of the bar may be squared off but must be capped. Nerf bars cannot extend more than 2½” from widest part of door. Any nerf bars in front of front tires or behind rear tires may be no wider than stock bumper. NO sharp edges allowed.



Front and rear OEM style bumpers are required to start heat and feature races.
Front bumper must be securely fastened. After market noses may use after market bumpers. Bumpers or wrecker loops are required on front and rear, without the time delay of removing the hood. Two (2) hooks required front and back. Bumpers must NOT extend wider than outside of rear tires.



A minimum of three (3) vertical windshield bars are required. Must be a minimum of 5/16” diameter steel, welded to the cage, and mounted in front of the driver.



Spoiler limited to 6 inches.  602 crate motor may have an 8” spoiler.



All cars must have ignition switch clearly labeled.
The car must be equipped with a kill switch to be located within reach when standing outside of the car and easily accessible to emergency personnel.



Maximum of 1 battery is allowed. Battery disconnect is required. Must be located behind the driver at deck height.  Must be securely mounted. NO batteries in driver’s compartment.  Battery may be charged by an alternator.




10” Hoosier asphalt pull offs, KK704’s, Hoosier H500, G60’s tires allowed. Durometer reading minimum 50 at end of race.  Grooved and siped tires are allowed. Steel wheels ONLY. Maximum wheel size allowed is 15” x10”. Two (2) beadlocks are allowed. Beadlock outer rings may be steel or aluminum. 1” O.D. lug nuts are required. ⅝ lug studs are recommended. Wheel spacers may be used with 5/8 studs only. Wheel adapters will be allowed.



Numbers must be 24” high and 4” wide on both sides of the car, and 28” tall on the roof and positioned so it can be read from the passenger side. Cars must be painted and numbered neatly and to be seen easily by the scorekeepers. The number on the roof is the most important number. Reflective vinyl is NOT recommended for roof application due to the readability. When positioning the number on the roof it should be readable from the passenger door.



Aluminum racing seats with right side rib protection is mandatory. A seat that provides both left and right side rib protection is recommended. Seat must be securely mounted. The racing seat must be bolted to a reinforced cross member and bracket(s). This cross member must be welded to the roll cage, not just the floorboard. The back of the seat must be supported and bolted to a flange that is connected by weld to the cage.



See General Rules for Protest Information.