Street Stock Rules
IF YOUR NOT LEGAL THE FIRST NIGHT YOU DON’T RACE
Minimum of a neck brace is required in all classes at any time you are on the track
Overall – 3100 lbs – full frame pocket to pocket with steel body @ 59.0% left (steel doors, fenders, and quarter panels)
3200 lbs – full frame pocket to pocket with a template or aluminum body with 59.0% left weight (ALL WEIGHTS ARE WITH DRIVER AND HELMET)
All added weights to car should be painted white and have your car number on it. No weight below the frame. All added weights shall be securely fastened with minimum ½” steel grade threaded rod. You must be 100% legal to run in this class or you will race with the pro late model division.
- Minimum wheelbase: 105
- Maximum track width 78” (by use of toe boards anywhere on wheels)
- Spoilers 6×60 centered on car no higher than 42” from the ground
- Minimum ride height 5”
- Minimum roof height: 47” (measured anywhere)
- Fuel cell mounted above centerline of rear end, 8” minimum clearance.
- Any template appearing body, aluminum or fiberglass is allowed (see weight rules above) No outlaw style bodies. Aftermarket nose and tail piece is OK. No splitters unless manufactured into the aftermarket nose. Aftermarket cars should weight 3200 lbs.
- Cowl and be used but air cleaner cannot be visible.
- Building of dash, front/rear firewalls OK. Minimum 1/8” steel under driver, no exceptions unless stock floor pan is used. Cockpit must remain open. Front to back under driver’s seat must be steel.
- Racing type seat is mandatory. No fiberglass.
- Seat belts must be properly installed-five point system only! Belts should be no older than 3 years old and in good condition.
- Full charged and properly mounted fire extinguisher is mandatory.
- Batteries must be securely fastened and covered.
- No mirrors, no radios
- Window net is mandatory.
- Frames must be stock spring pocket to spring pocket
- Safety constructed 4 post roll cage with minimum 3 bars on driver’s side. Using 1 ½” OD tubing and .090 wall. Front and rear hoop OK
- Driver’s door must have a 10” x 30” x 1/8” minimum steel plate welded or bolted securely to the cage.
- Tubular steering shaft with minimum of two universal joints OK. Collapsible steering shaft highly recommended.
- No aftermarket suspension parts – stock mounts, stock location, stock rear frame rails may be replaced from behind the spring pockets rearward to the bumper with 2” x 3” steel tubing.
- Stock 4 link only in stock location. Ten or twelve bolt GM rear ends OK. Ford 9” rear ends also OK. All rear ends must have steel tubes only. No other modifications. ( no limited slip differentials like Gold Tracks or similar) NO ALUMINUM SUSPENSION PARTS, ANYWHERE! We recommend aftermarket rear axles for added strength. Adjustable Heims on rear trailing arms OK. Leaf spring cars must add 50 pounds.
- A-arms, rotors, calipers, tie rods, steering box, etc to be stock OEM. Trailing arms can be aftermarket or homemade but must be steel and mounted in rubber or spherical bearing. NO THREE LINK OR PANHARD BARS.
- Screw jacks on all four corners OK
- Minimum spring diameter is 5” racing style.
- Aftermarket upper A-arms OK. No adjustable ball joints.
- Any steel body shock with no Schrader valve, with no internal or external bump springs. Tie down shocks OK Must meet 5” ride height rule before and after the race.
- Aftermarket gas pedal, brake pedal, in car brake adjuster OK
- Rear disc brakes OK. Single piston steel or aluminum calipers OK. ALL FOUR BRAKES MUST BE OPERATIONAL.
- Engine must be stock appearing, all cast iron – Maximum 2” set back, but must not exceed 4” This will be measured from number one spark plug to ball joint centerline. Setback between 2” and 4” require 50 lbs. added to the right front corner of the car per tech officials discretion.
- Roller cams, roller rockers assemblies OK
- Intake: cast iron or aluminum
- Carbs: 2 or 4 barrel OK
- Max. adapter spacer is 1” any material
- No aftermarket electrical fuel pumps.
- Stock style HEI or MSD style ignition OK
- Any header with any exhaust, single or dual. Must exit behind the driver and not pass through driver’s compartment. 100DB muffler Mandatory!
- Transmission: automatic w/ stock 10.5” torque converter or manual with 11” or mini Clutch OK. Reverse gear is mandatory, no direct drive or aftermarket transmissions. Aluminum flywheel is OK.
- Car must idle in gears w/ hands on the steering wheel.
- No transmission coolers in driver’s compartment.
- Drive shaft hoop mandatory!
- Stock or aluminum radiator in stock location. NO ANTIFREEZE!
- Tires – Hoosier 800 Tires
- All wheels are to be 8” steel safety type only – with 1” lug nuts recommended.
ANY INTERPRETATION OR CHANGING OF THESE RULES IS AT THE DISCRETION OF THE OFFICIALS. THEIR DECISION IS FINAL. ANY MAJOR INFRACTION WILL BE ADDRESSED AS A FORFEITURE OF POINTS AND MONEY EARNED FOR THE NIGHT. THIS WILL BE AT THE DISCRETION OF THE TECH INSPECTOR. FIGHTING WILL NOT BE TOLERATED.
Plymouth Motor Speedway reserves the right to change, delete or add to rules throughout the racing season. The management reserves the right of interpretation of all rules and the right to inspect and reject any car and/or driver, crew member, etc. during the racing program.