Afton Motorsports Park Street Stock Class Rules

The Street Stock class rules for Afton Motorsports Park are listed on this and four other pages, linked to below.


Page 1 of Rules: [Go to page 1] Includes Eligibility Requirements, Former Prostock/Super Stocks, Bodies and Aluminum Body Rules.
Page 2 of Rules: [Go to page 2] Includes Seats/Interiors, Roll Cage and Suspension.
Page 3 of Rules: [Drivetrain] [Weight] [Wheels and Tires] [Brakes] [Shocks] [Transmission] [Engine]
Page 4 of Rules: [Go to page 4] (Engine continued) Includes Vortec Head and Intake Heads, Headers, Intake, Ignition, Cooling System, Fuel Systems, Carburetor, Option 602 Street Stock Engine
Page 5 of Rules: [Go to page 5] Includes Body Installation Guidelines Diagram.

[PDF of Street Stock Rules] [Download Adobe Acrobat]

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  1. Stock type rear ends only. May be from different size car.
  2. Ford 9' floater rears allowed. Components must be steel. (Internal and external)
  3. No wide 5 bolt patterns allowed.
  4. Rear lower control arm bracket center hole may not exceed 31/2" from bottom of axle tube.
  5. Welded or locked rears allowed.
  6. Spools allowed, no aluminum parts permitted.
  7. Racing axles allowed but no ratchet type differentials, Gold Trac, or any other aftermarket traction control devices allowed.
  8. Rear control arms may be aftermarket or fabricated. Lower rear must maintain OEM length, and mount in OEM locations.
  9. NO slotted holes in either rearend or on frame.
  10. Upper control arms may be adjustable and may use bushings or rod ends.
  11. Lower control arms may not be adjustable and must utilize stock style bushings.
  12. Drive shafts will be painted white and have a minimum of two steel safety hoops near front and rear.
  13. No chains, bungee cords or tin strapping.
  14. No aluminum drive shafts or half shafts allowed. Minimum 2 inch diameter steel driveshaft.


  1. All bolt on lead or added weights must be securely mounted, brightly painted, and have car number on it.
  2. All cars must weigh a minimum of 3000 lbs after racing with driver, no allowances made for water or fuel.


  1. 8' steel wheels, may be any offset.
  2. Aftermarket steel rims highly recommended.
  3. Bead locks allowed on 4 wheels.
  4. No wide 5, aluminum or magnesium wheels.
  5. American Racer 70/245 non DOT racing tire is the track tire.
  6. No tire softeners or treatments allowed.
  7. Grooving or siping is allowed.
  8. Minimum of 5 lug nuts per wheel at all times.
  9. 1" steel lug nuts mandatory on all four corners with at least 1/2" studs, 5/8 recommended.
  10. ROC SERIES/SPECIALEVENTS: Both rear tires must be the track tire used by the hosting track. Fronts are not mandated and open to driver's choice.


  1. Must have operable and effective 4 wheel brakes.
  2. Dual master cylinder allowed.
  3. Front to rear brake bias adjuster allowed.
  4. Balance bars are allowed with external or remote adjusters.
  5. Right front brake shut off valve allowed may be within reach of driver.
  6. All right front brake components must be in place.
  7. Rear stock disc brakes allowed, but must be OEM type systems.
  8. No aluminum rotors or dual piston calipers.
  9. No electric brake shut-off.


  1. Steel bodied shocks only, must be Non-adjustable, one per corner.
  2. Steel bodied after market shocks with welded heim joint ends are allowed. Upper and lower mounts may be fabricated. Must be non-adjustable. (Example:No multiple holes)

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  1. Stock automatic or stock manual transmissions only, with all gears working, including reverse.
  2. Automatic transmissions must have functional 11" torque convertor with no internal modifications allowed.
  3. No hollow converters allowed or any method of creating direct drive systems.
  4. Manual transmissions must be OEM production type transmissions. Three or four speed transmissions only.
  5. All forward and reverse gears must be in working order.
  6. Manual transmission must be operated by manual shifter within reach of driver.
  7. Clutch must be single disk, OEM style, minimum 10 ½ inch diameter. No metallic clutch disks allowed.
  8. Hydraulic release bearing allowed.
  9. Flywheel, pressure plate, clutch disc, and hardware must weigh a minimum of 35lbs.
  10. Manual transmission must have full steel 360 degree bell housing.

Optional Transmission, Clutch and Weight Rules:

A) Legal open motor with automatic or standard transmission by above rules: 2900 lbs.
B) Legal open motor with aftermarket transmission (Bert, Falcon, Brinn) or modified power glide (no converter) or racing clutch (small diameter/light weight): 3100 lbs.
C) Crate motor with open transmission (Bert, Falcon, Brinn) and Four Barrel Carb. (650 cfm): 3125 lbs.

Note: All standard transmission with clutch and flywheel must be equipped with a 360 degree steel bell housing. Aftermarket transmission cars (Bert, Falcon, Brinn) can use aluminum 360 degree bell housing.
Approved Transmissions:
Falcon: P/N 60100
Brinn: P/N 70001

I-88 reserves the right to adjust these weight rules at any time if deemed necessary for the purpose of fair competition for the class.


  1. Non-Performance World Product Replacement Chevy Heads allowed. Part numbers World 043600 or World 043610.
  2. Bow Tie Allowed
  3. No hand grinding, sanding, blending, or de-burring where a cutter or stone leaves off.
  4. Sand blasting, bead blasting, add dipping, porting, polishing, and welding are prohibited.
  5. No titanium valve train parts allowed. All Rockers 1.5 - 1.6
  6. Screw in studs and guide plates.
  7. No relieving or unshrounding of valves in combustion chamber.
  8. May run double valve springs.
  9. All factory casting numbers must remain visible.
  10. No aluminum heads, even If they were OEM parts.
  11. Maximum cubic inch 360. Maximum displacement:
    • GM: 350ci+.060", 4" bore x 3.480" stroke
    • Ford: 351ci+.060", 4" bore x 3.5" stroke
    • Ford: 347ci+.060", 4" bore x 3.4" stroke
    • Chrysler: 360ci+ .060", 4" bore x 3.578" stroke
    • Chrysler: 340ci+.060", 4.040" bore x 3.13" stroke
    • Blocks may be decked, but piston must not extend above deck at all.
  12. Wet sump oil pans only.
  13. Flat tappet cams only.

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