Super Stock Rules

Irwindale Speedway Super Stock Rules 2019

For Downloadable PDF version: 2019 IS Super Stock rules

No pretense is made for having designed a foolproof set of rules and regulations.  If this rulebook does not specifically state that you can alter, change, or otherwise modify something on your car, you should consider it a violation of these rules.  No part is deemed to have been approved by Irwindale Speedway by passing through prior technical inspections.


The Tech 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. Any deviation of these rules is left to the discretion of the Tech Director.



  2. A. Any 1960 or newer sedan. No Station Wagons, Convertibles, Pick-Ups, Jeeps, etc.
  3. All cars must maintain stock OEM type body. Stock appearing fabricated door panels, rear quarter panels and deck lid allowed. No interchanging of manufacturer bodies and frames.
  4. Rear deck lid spoiler allowed maximum 5” tall and no wider than 60” wide.
  5. No front lower spoilers allowed. Air scoop for radiator allowed, no wider than radiator.
  6. A minimum of four (4) inches from body to ground.
  7. Cars with fiberglass roof and/or quarter panels add 40#.
  9. A. Full NASCAR type roll cages mandatory. Main roll bars must be a minimum of 75” O.D. x .090” wall steel tubing.
  10. Minimum of four (4) door bars required on both sides. Right side can be straight. C.  Rear down bars must extend to rear cross member.
  11. Fuel cell protector required.
  12. Main roll cage uprights must be fastened to floor of uni-body cars with a minimum 3/16” thick

plate, top and bottom, at all four corners.  Plate must be a minimum of 4” square.

  1. F. Roll bar padding must be used at any point where driver may make contact.
  2. G. Door bars must be covered with a minimum 1/16” thick steel metal plate, top to bottom, from front and rear uprights, welded to outside of bars.
  4. A. A windshield made of 1/8” thick clear polycarbonate must be use
  5. Each car may have a rear window made of clear LEXAN.
  6. No right side window of any type is allowed.
  7. Side quarter windows can be replaced with LEXAN.
  8. Driver side window net is required on all cars. Net must be equipped with a quick-release device on the top left corner.
  9. Left side mirrors allowed.
  11. A. Minimum of four (4) inches of ground clearance.
  12. Minimum weight 3150 lbs with driver.
  13. Cars stock floorboard and firewall – 50# weight break.
  14. All cars maximum left side weight with driver cannot be over 55%.
  15. Wheelbase must be within ½” of other side.
  16. After market fabricated replacement front clip or under 108” wheelbase add 50#.
  18. A. Stock type bumpers are require
  19. Front and rear bumper must be fastened to the fender and or quarter panel.
  20. ENGINE
  21. A. Cylinder compression limited to 200 lbs.

Ford 351 C.I.

Chevrolet 350 C.I. Dodge 360 C.I.

Plus max .060 overbore

Maximum cubic inch 360cc. B.  A stock GM crate engine P/N 19258602 allowed to factory specs.

  1. Engine must be in stock location. D. Engine oil coolers allowed.
  2. E. Aftermarket oil pans, valve covers, water pump, fan pulleys are allowe
  3. F. No “stroker” or lightweight cranks allowed, factory OEM cranks only.
  4. G. Heads: Stock cast iron heads only. A stock head will be characterized as a cylinder head which

was offered as standard equipment with no performance advantage.

  1. H. No special performance options will be allowed, including but not limited to, oversize valves, special cut valves, relocated intake or exhaust bowls or ports.
  2. I. No porting or polishing will be allowe
  3. J. Vortec heads are allowe
  4. K. Stock steel, stock stainless steel valve train components only, 5 ratio roller rockers allowed.

NO shaft rockers.

  1. L. Screw in studs and guide plates allowe
  2. M. Engine Blocks: Stock cast iron blocks only. No modifications allowe N. Stock stroke for engine being used, exp. 350 C.I. Chevy 3.48” stroke.
  3. O. Stock rods only after market rod bolts OK. P. No roller or mushroom lifters allowe
  4. Q. Stock type timing chain and gears only.
  6. A. All cars must run Holley #4412 2 barrell gauge legal carburetor except for the following: Gaskets, bowl seals, accelerator pump squirter, power valve, jets, sight plug, choked plate and shaft may be remove
  7. Two (2) carburetor return springs required.
  8. Maximum 1” carburetor adapter allowed.
  10. A. No cold air box allowe K&N air filters are allowed.
  12. A. Engine oil pan height must not be less than current car ride-height rule.
  13. Crankshaft must be centered within one (1) inch of the vehicle’s front frame clip.
  14. D. Minimum clearance between the center of the crankshaft and the ground must be5” inches.
  16. A. Stock HEI type ignition only. No performance after market or MSD distributors allowe
  17. All cars must be equipped with a master electrical switch located in the cockpit of the car. The switch must be within reach of the driver and safety crew from the both sides of the car.
  18. Batteries must be securely mounted within the confines of the body and behind the driver.
  19. D. Batteries must be contained in a secure containe No marine or plastic boxes allowed.
  21. A. Electric fans are permitte
  22. Water overflow catch can unit required vented out to windshield.
  23. C. Water wetter permitte
  25. A. Stock manifolds are permitted.
  26. Headers are permitted. Must be 1 5/8” tube.  No stepped or Tri Y’s allowed.
  27. An approved muffler is mandatory, must not exceed 90 db @100 feet. D. Exhaust must extend past driver’s compartment.
  29. A. Clutch must be stock type only.
  30. Steel flywheels only.
  31. D. Scatter shields mandatory
  32. E. No lightening of flywheel permitte
  33. F. Locked, limited slip, or positive-traction differentials, is permitte
  34. G. Floater type rear ends are permitte
  35. H. Automatic transmissions optional, torque converter must be operationa
  36. I. Ford 9” rear end allowe
  37. Two (2) driveline straps, 1.5” x 1/4” required, mounting to be within 6” of the U-Joints.
  38. Magnetic steel drive shaft must be painted white.
  40. A. Stock OEM type lower control arm Must be equal length.
  41. Tubular upper A-arms allowed.
  42. Stock OEM Spindles only. No aftermarket or tubular spindle.
  43. Stock upper control arm mounting may be moved for caster/camber, must remain stock height. D. Rated springs are allowed, front and rear.
  44. E. Lowering blocks allowe
  45. F. All other suspension components must be of original design and origin for the chassis use
  46. Maximum overall width (front or rear) shall not exceed 78” from outside of tire to outside of tire at spindle height with driver in the car.
  47. G. Steel shocks Non-adjustable, rebuildable, and/or re-valveable type shocks OK. Shocks must be mounted in stock location. Shocks not mounted in stock location add 25# penalty. Maximum retail price $175
  48. H. Adjustable spring spacers or weight jacks allowe
  49. I. After market pedal or master cylinder assemblies allowe
  50. J. Rear disc brakes allowe
  51. K. One adjustable brake bias valves allowe
  52. Any one piece steel sway bar mounted in stock location allowed.
  54. A. Stock steering components only.
  55. Quick release steering wheels are required.
  56. Steering column must be collapsible. Two U joints are acceptable.
  58. A. Sunoco 110 or pump gas will be permitte The chemical composition of the fuel may not be altered by any means.
  59. All cars must be equipped with an approved fuel cell mounted in the trunk area.
  60. Fuel cell must be mounted with steel framework (1 inch x 1 inch, .065 inch minimum).
  61. D. Fuel cell must be enclosed in a steel bo Ground strap required from fill neck to frame.
  62. E. Maximum fuel capacity – 22 gallons.
  63. F. No electric fuel pumps permitte
  65. A. Steel wheels are mandatory, maximum 8” width any offset.
  66. The use of any bleeder valve is prohibited.
  67. Wheel spacers allowed.
  68. The track tire is the Hoosier #970. No Star tires.
  69. G. TIRE PURCHASING RULE AS FOLLOWS: At a competitors first race event he/she may purchase a maximum of (4) four new tires. At each race there after he/she a maximum of (1) one new tire. You must start the race on the tires you qualify on.
  70. H. In the event that a competitor flattens or damages a new tire, tire must be removed and inspected

by head tech official before replacement will be allowed.

  2. A. For all safety equipment. It will be the sole responsibility of the driver, not Irwindale Speedway, their agents/officials or corporate officers to ensure that his/her safety equipment is correctly installed, maintained, and properly use  Please refer to manufacturer installation and guide lines and adhere to them.
  3. Aluminum professionally built high back racing seat required. No plastic, etc. C.  Seat must be securely bolted to a mount assembly that is an integral part of the roll cage.
  4. A five (5) point safety harness, with quick release is mandatory.
  5. Safety harnesses/seat belts may be no more than three (3) years old.
  6. Helmets; Head and Neck Restraint Devices:
  7. i. Snell SA2010 or SA2015 helmet require
  8. ii. Full face helmets with Lexan face shield recommende

iii.    A HANS or Hutchens type head and neck restraint device is recommended.

  1. J. Window net mandator
  2. K. Current test date fire extinguisher to be installed in the car within drivers reach while strapped in.
  3. O. All cars will be required to have in their pits a minimum of one five pound, Halon or dry

chemical fire extinguisher.

  2. A. Numbers will be a minimum of 20” on the roof and both door panels.
  3. Advertising or names on the windshield is not permitted. Reserved for a series sponsor.
  4. Advertising that is deemed to be unsuitable/offensive, will not be allowed.
  6. A. You must have a spotter stand in the spotter stand at all times car is on track.
  8. A. No electronic monitoring computer device
  9. No electronic traction control devices allowed.             1.31.19