Street Stock Rules

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CENTRAL MISSOURI SPEEDWAY

2011

STREET STOCK RULES 

The spirit and intent of these rules is to keep down the cost of racing.  Any attempt to circumvent this intent will not be tolerated.  The 2011 rules have not changed from the previous season.  

1) BODY / FRAME / BUMPERS:  

  1. Must be unaltered OEM, and centered over wheel-wells (front-to-rear and side-to-side).
  2. Any American OEM full body, rear-wheel drive passenger cars, 1964 or newer allowed.  Full frame or 1970 to 1982 Camaros with 108-inch wheel base, minimum of 107-inch wheel base allowed.  Wheel base must be 107-inch minimum both sides measured center lower ball joint to center rear axle housing.  No sports cars, i.e., Mustangs or Corvettes.  No station wagons or trucks.
  3. Spoilers, hood scoops, ground effects, skirting, and reflective body panels allowed.  Spoiler limitations:  Six (6) inches maximum height, sixty-six (66) inches wide.
  4. Sunroofs and T-tops must be enclosed.
  5. Rear edge of trunk may be trimmed and rear tail-light support removed only if an after-market tailpiece is used.
  6. Trunk floor must be removed over rear-end housing; entire trunk floor may be removed for weight jack use.
  7. Front of car must be stock appearing.  OEM or aftermarket plastic nose and tail pieces allowed (designed/constructed to match body).  No wedge noses.
  8. All body panels may be gutted, including fenders, doors, hood, roof, quarters and trunk.  Must remain original size.
  9. Hood must be separate from fenders and in OEM location with rear sealed off from driver’s compartment with metal.  Clear air cleaner or hole for air cleaner allowed provided it is boxed in completely with no openings.
  10. Inner wheel-wells may be removed.  Wheel-wells may be trimmed for tire clearance purposes.
  11. All windows must remain open.  Opera windows may be covered with clear Lexan, no decals! 
  12. Maximum 7-inch metal sun visor may be added to top of windshield opening. 
  13. After-market or home-built bumpers must stay within quarters of the body, must have two tethers attached to rear bumper.  Bumper edges must be rounded and smooth.          

2) DRIVER COMPARTMENT:  

  1. Minimum of three windshield bars in front of driver.
  2. Aluminum high-back seats only, which must be bolted in using minimum 0.375-inch bolts with oversized washers to keep bolt from protruding through seat.
  3. Seat must remain inside all confines of the roll cage.  Driver must be sealed off from track, driveline, engine, and fuel cell.
  4. Kick and rocker panels may be removed.
  5. Front OEM firewall may be replaced using steel fabricated firewall, 18-gauge or minimum 0.049-inch thickness.  Bottom of firewall may be no further back than rear of oval body mount frame hole. 
  6. Dash must not extend more than 24 inches back from top of firewall.  Dash must be flat.  Rear may be no higher than front except for cowl in front of the driver.
  7. 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.  May be no higher or lower than frame rail.  Exception is maximum 8-inch tall driveshaft tunnel.  Tunnel must remain similar to OEM tunnel in size.
  8. Passenger side may be covered, but a removable or hinged inspection cover, at least 12-inch by 12-inch must be installed.
  9. 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.
  10. No driver-adjustable devices are allowed while car is in competition except brake adjuster.
  11. No mirrors of any kind.  Rearview mirrors or reflective materials not allowed.
  12. One 360-degree driveshaft loop constructed of 1/8-inch x 2-inch steel and securely mounted to frame, cross member or floor pan between 6 inches and 9 inches behind yoke.  When mounted to floor pan, loop brackets must be secured with 6-inch square 1/4-inch plate top and bottom of floor pan and bolted at the corners with minimum 3/8 bolts.

3) ROLL CAGE / BRACES:  

  1. Must be 4-post cage with rear and front brace loops.  Loops must be the width of the frame with a maximum of 2 horizontal and 2 vertical bars behind front bumper.
  2. There must be a minimum of 4 side door bars on the driver’s side.
  3. All cage tubing must be minimum 1-1/2 inch O.D. and minimum of .095 wall thick.
  4. All cage construction will be inspected by the Tech Official and must be approved.
  5. Plate must cover area from top door bar to frame and from rear down post to five (5) inches in front of seat.
  6. Must be visible for inspection.

4) TIRES / WHEELS:  

  1. Maximum tire sizes allowed:  275-60/15 or 255-70/15.  Must be DOT approved.
  2. No truck, R.V. or mud and snow tires.  No recaps.
  3. I.M.C.A. stamped Hoosier G-60, McCreary American Racer (KK-704) allowed. Modified takeoffs allowed.                                                      
  4. Tire siping, grooving, and grinding allowed.
  5. Steel wheels only with maximum 8-inch bead width.
  6. Bead lock and/or mud plug on all four wheels is allowed.
  7. No bleed-off valves.

5) SUSPENSION / STEERING / SHOCKS / DIFFERENTIALS:  

  1. All components and mounts must be steel, unaltered OEM, in OEM location and match frame.
  2. Rubber, nylon or steel lower A-frame bushings only.  No offset bushings allowed.
  3. No sway bars.  Exceptions:  Weight jacks allowed, must be in original centerline of spring tower; OEM upper A-frame mount may be moved or replaced with after-market steel mount matching upper A-frame bolt on design; OEM or OEM replacement ball joints allowed.  For 1978-1987 GM mid-sized metric frames, OEM upper A-frame may be replaced using one piece after-market upper A-frame.
  4. Shock location may be moved and may go through center of after-market upper A-frame, but frame cannot be altered in any way.  Single-hole shock mounts only.
  5. All components must be steel, unaltered OEM, in OEM location and match frame.  Exceptions:  Bolt-on spindle savers allowed, OEM steering column may be replaced with steel knuckles and steel steering shafts (collapsible recommended).
  6. Quick-release required; steering quickener and steering wheel may be aluminum.
  7. One steel nonadjustable unaltered shock per wheel.  Competitors may claim another competitor’s shock.  Competitor being claimed must have finished in the top four in the A-main event in order for claim to be made.  The claimer must be a fellow driver and must present the sum of 100 dollars cash to be paid to designated CMS official in the designated technical-inspection area immediately after the A-main event.  A maximum of one shock per claimer, per night may be claimed.  Only one shock may be claimed on each competing car per night.  I.E., drivers A, B, and C cannot each claim a shock on driver D’s car all in one night.  Claims must be made not later than 10 minutes upon conclusion of race.
  8. No coil-over, air, or remote reservoir shocks.  No Schrader or bladder-type valve shocks allowed.  No coil-over eliminators allowed.
  9. One steel spring per wheel only.
  10. All coil springs must be minimum 4.5 inches O.D. and non-progressive.
  11. All components and mounts must be steel, unaltered OEM, in OEM location, and match frame.
  12. No independent rear suspension.
  13. Rubber or nylon control arm bushings only.  No offset bushings allowed.
  14. Welded single-hole shock mounts only.  Exceptions:  Coil springs may be moved; however, center line of axle tube may be no further forward than the front of spring or no further back than rear of spring; shocks may be moved, but must remain behind housing.  Lower control arm mounts on rear-end may have multiple holes (maximum of five) for adjustment.
  15. Upper control arm mounts on rear-end must be level with each other.
  16. Differentials:  Any steel approved OEM passenger car or truck non-cambered rear end (housing and carrier) allowed.  Safety hubs (floater) allowed.  No sway or panhard bars.  No torque-dividing differentials.
  17. All components must be steel, exceptions:  lowering blocks, axle cap, and drive flange may be aluminum.  Adjustable lowering blocks allowed.  Adjustable rear leaf-spring shackles and/or leaf-spring sliders are allowed.
  18. A one-inch inspection hole in housing required.  Full steel spool, steel mini spool, or welded rear-end only.  Steel axles only. 
  19. Quick-change devices not allowed.  One-piece drive flanges only.  

6) BRAKES:  

  1. Steel, unaltered OEM, or unaltered OEM replacement, operative four-wheel, drum, or disc type brakes allowed.
  2. Brakes must operate on all four wheels.  No brake shutoff or pressure-sensitive devices.  No floating brakes.  Brake lines must be visible.
  3. Front components must match frame and maintain minimum OEM dimensions for hubs/rotors and calipers, cannot be lightened.
  4. OEM diameter caliper pistons only.  Bolt pattern may be changed.  Larger studs allowed.
  5. Vented rotors only, no scalloped or ceramic coated rotors.  Rear rotors may be after-market 0.810 inch thick (new).
  6. One front-to-rear proportioning device allowed.
  7. After-market pedal assembly allowed.

7) TRANSMISSIONS / DRIVE SHAFTS:  

  1. Transmission must be OEM.  Must have at least two forward gears and one reverse, plus neutral position.  With the motor running and car in a still position, must be able to engage car in gear and move forward and then backwards.  Car must start and move under own power.
  2. Only OEM production-type transmissions allowed:  two-speed, three-speed, four-speed, and automatics.  No five-speed (or more) transmissions, “in and out” boxes, or quick change devices allowed.
  3. Functioning shift levers must be in OEM location.
  4. Flywheel/flex plate must be bolted directly to end of the crankshaft and pressure plate must be bolted directly to flywheel/flex plate.  One flywheel/flex plate only.  All drive-line components within bell-housing must rotate consistent with engine RPM while car is in any gear.  Unaltered flex plate must be full OEM, or OEM replacement.
  5. Automatic types:  Must remain in OEM or OEM replacement case, with a functioning OEM-appearing pump.  Aluminum OEM bell-housing may be replaced with after-market explosion-proof aluminum bell-housing. Original OEM bell-housing must have approved scatter shield constructed of minimum 0.125-inch by 3-inch steel, 270 degrees around flex plate. Manual bump starts allowed.  Coupler allowed.
  6. Manual types:  Must be OEM or OEM replacement case and have a working single-disc or multi-disc mini-clutch.  Must have explosion-proof, steel bell-housing.
  7. Bert, Brinn, In-and-Out, or Layne transmissions are not allowed.

8) ENGINES / CARBURETOR:  

  1. Engine setback:  No further back than center of number one plug hole with center upper ball joint.  Frame and cross member may not be altered for engine placement.  Engine mount holes cannot be removed or altered on block.
  2. Aftermarket engine mounts allowed, including mid-plate.
  3. Engine must be OEM appearing and must be usable in conventional passenger car without alteration.  GM with GM, Ford with Ford, Chrysler with Chrysler, etc.
  4. Radiator must be mounted in front of engine.  Cooling system may be modified.  Overflow tubes must be directed to ground.
  5. Any American make engine allowed.  Steel 23-degree heads, block and oil pan only.  OEM passenger vehicle production block only.  GM Bowtie, Ford SVO, or Chrysler W blocks not allowed.  No cubic inch limit.
  6. Castings and fittings cannot be changed, no machine work on outside of engine.
  7. Full roller rocker arms allowed.  Stud girdles allowed and shaft rocker arms.
  8. Flat tappet cam/lifters only.  No mushroom lifters.  Cannot alter lifter bores.
  9. After-market aluminum intakes allowed. 
  10. Steel or aluminum water pumps allowed.
  11. Wet sump oiling system only.  Accumulator allowed but cannot be located between seat and door bars.
  12. Must run two-barrel Holley #4412, 500 c.f.m. model.  Carburetor must pass track go/no-go gauge.  Choke plate may be removed.
  13. No vacuum leaks between air cleaner and intake valve.  Any adapter plate, and/or spacer, may not exceed 1.015 inch.  A maximum .065 gasket may be used on each side of spacer.  No spacer will be allowed between the bottom of air cleaner and carburetor.
  14. Fuel pump (mechanical types only) must be in original mounting position.  Belt-drive pumps approved.  No electric pumps.
  15. Maximum one round air cleaner may be used.  Maximum size:  14-inch diameter by 4-inches thick.  Air cleaner must be made of solid metal from top to bottom.

9) FUEL / FUEL CELL / FUEL SYSTEM / EXHAUST:  

  1. Pump gasoline or any fuel product sold at local fuel stations for OEM vehicles including E85/95 only.  Racing fuel allowed.  Alcohol, performance-enhancing, or scented additives not allowed.
  2. Fuel cells must have tip-over valve or check ball-type valve installed on any vent to or on the fuel cell.  Mechanical OEM-type push-rod fuel pumps only.
  3. No fuel cells larger than 22 gallons.  Racing fuel cells required.  Must be in minimum 20-gauge steel container and securely fastened in trunk above top of rear frame rails, behind the rear tires and no further forward than factory seam where rear frame rail can be replaced with a minimum of two solid steel straps around entire cell, 2 inches wide and 0.125-inches thick.  No fuel cells allowed over rear end housing.  No adjustable fuel cell mounts.
  4. Metal firewall must be between driver and fuel cell.  All cell mounts must be steel, securely welded to frame/cage.
  5. Fuel cell vents, including cap vent, must have check valves.  If the fuel cell does not have an aircraft-style positive seal filler neck/cap system, a flapper, spring, or ball-type filler rollover valve is required.
  6. Fuel lines through driver compartment must run through metal pipe or metal conduit.
  7. One fuel filter only.  Fuel filter cannot be in driver’s compartment.  No cool cans.
  8. Exhaust:  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 merge collectors and no exhaust sensors.         

10) CAR WEIGHT / WEIGHTS:  

  1. Car with driver will weigh a minimum of 3,100 pounds at end of all races.
  2. No weights or loose objects in driver’s compartment or on outside of body. 
  3. All weights must be securely mounted to frame or roll cage and painted white with car number on them.  Weights must be attached with at least two 0.5-inch bolts.
  4. No titanium, magnesium, or carbon fiber products. No gun-drilled, tubular, hollow bolts or studs.  Use steel fasteners only.

11) ELECTRICAL / ELECTRONIC SYSTEM:  

  1. One 12-volt battery only, which must be securely mounted between frame rails, and positive terminal must be covered.
  2. Battery must be in Marine-type case if mounted in driver’s compartment.
  3. Starter must bolt in OEM location.
  4. Car must fire under its own power at starting line/staging area without being pushed, pulled, or aided in any manner.
  5. No unapproved cameras, transmitting, traction control, 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.
  6. No adjustable ignition control boxes.  One high-end rev-limiter ignition box change permitted only.  Setting may be changed through one chip only.  No crank triggered ignition.  No alternators or magnetos.
  7. HEI and MSD ignition systems only.  Can use MSD 6A or 6AL boxes.  One ignition box per car.  

Must have visible numbers on back of car.  

Refer to “Track Rules, Regulations, and Car Specifications” booklet for additional information.  If you do not have this booklet, ask for one at the registration/pill-draw tower.  

NO SOFTENING OR CONDITIONING OF TIRES OTHER THAN MENTIONED IN THESE RULES.  Tires will be checked by tire durometer on the inside of the tire only.  Lowest tire number point is fifty (50).  NO ALTERING TIRE COMPOUND!

 

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