Thunder Mountain Speedway


Site Under Construction


Updated March 2016

The rules set forth herein are designed to provide fair parameters for competition and a high level of safety. NO expressed or implied warranty of safety shall result from publications of or compliance with these rules and regulations, they are intended as a guide for the conduct of sport and are no way a guarantee against injury or death to a participant, spectator or official. Driver/ car owner is legally responsible for all crew signed in under car.

It is the Driver/Car owners' responsibility to ensure his or her car is legal, if there is a question about the rules, email or phone a TMS Director before you show up, non conforming cars will not be allowed to run except for minor variations. Tires and Safety rules are subjected to review by Tech only.


Any 4-passenger sedan produced with a 2.3 liter or smaller engine, with maximum 103” wheelbase or a mini truck no longer than 108" wheelbase. 

All cars will weigh I pound per cubic centimeter including driver – weight distribution L 55% with driver in the car.  A 1% margin of error will be allowed in car weights. Weight is subject to tech. Any car with apparent edge will have weight added to tighten field (AT TECHMANS DISCRETION).

  1. Body classifications are limited to Canadian, American or Foreign subcompact automobiles.

JDM (Japanese Domestic Market) and vehicles not produced for the North American market are not eligible.  No right hand drive vehicles.

  1. Must meet Canadian/American factory published specifications for the year, make and model of car.
  2. Wheelbase and engine cc must be displayed on right side of hood or windshield.
  3. Cars must have steel roof.
  4. All holes in the flooring and firewalls will be sealed with minimum 20-gauge steel.
  5. Hood and trunk lids must be securely fastened and easily removable by Safety Personnel.  Newer style body, skin only, may be used on older style chassis.  Donor bodies to conform to maximum wheelbase rule.  Fenders extend – not the frame.  The installation must be done safely and neatly. Complete shell may only be used if stock firewall mounts fit.  Body must be complete and remain neat in the stock location.  Stock appearing aftermarket steel bodies allowed. Fiberglass bodies allowed with 50lb weight penalty.  Plastic nose and tailpieces permitted.
  6. Glass must be removed from the car except for the windshield.

  1. No door handles or chrome to be left on to constitute a safety hazard.  All decorative chrome must be secured or removed.
  2. Must have bumpers front and rear.  Bumpers must be mounted in stock location and be of the same basic design as stock factory bumper.  No crash bar style bumpers allowed.  Bumpers must have rounded ends so that they cannot be torn off or hooked.  Must be strapped to the body.  Cars must have accessible tow hooks front and rear of car and be behind bumpers so as to be safe from impact.
  3. No sports cars or two seat cars.  No convertibles or four wheel drives.
  4. Body swaps are allowed and all parts and donor pieces must comply with (A), (B), and (C).
  5. May use aftermarket steering column.  Must have at least 1 (one) u joint.  Pedals must remain stock and remain in stock location.
  6. Oil pan and transmission MUST NOT be the lowest point on cars.
  7. Tight fitting rub rails allowed.
  8. Any new model cars not already in competition must be passed by tech committee before building.


  1. May completely gut interior.
  2. May remove trunk floor, but stock unibody sub frame must be intact.
  3. Must have rear firewall.
  4. May completely strip doors, trunk, and hood, but basic interior structure must be complete (check with tech before cutting).
  5. Cars with structural suspension points in front suspension must not remove front inner fender wells, but should tie struts into cage structure.
  6. On strut cars, you can remove all nonstructural metal up to the front of the strut towers, but any frame must remain intact and stock.


  1. All suspension components must be stock for the year and make of that car.
  2. All pivot points and mounting points must remain in stock location.
  3. May change springs and shocks
  4. May move shock mounting points.
  5. Weight jacks are allowed.
  6. May modify mounting point on top of strut cars for camber/caster adjustment.


  1. Any gear ration allowed.
  2. May swap rear ends, but must retain all stock mounting points.
  3. Locked differentials allowed.


  1. All 4 brakes must be in working order.
  2. Must be stock for that make and model.
  3. Stock rear disc brakes allowed, but must be stock to make and model.
  4. Brake bias valves allowed.
  5. Single stock style master cylinder only.  


  1. Tires will be maximum 7” tread face Hoosier Racing tire; short trackers, 23” or 23.5” 700 compound on 13”x7” maximum rims.  8” tread face on 13”x7” rims allowed.
  2. 13” steel or aluminum wheels to a maximum 7” rim width.
  3. Tires must not protrude outside of fenders or fender flares.


  1. Must be make to make.
  2. Engine must remain in stock location with no modifications to the firewall.  May modify stock mounts to solid mounts. 
  3. Any pushrod or single overhead cam engine, with no more than 2 valves per cylinder with a maximum displacement of 2300cc (maximum .060 overbore) or subject to weight penalty.
  4. All engine components must remain stock (no knife edge cranks, custom rods, exotic pistons, etc.)
  5. Any flat tappet camshaft allowed.  Must be normally aspirated (no turbos, superchargers, NOS, etc.).
  6. Flat top pistons only. Must meet stock specs, but may be aftermarket TRW, Sealed Power, etc. Keith Black pistons may be allowed but must meet stock specs. No lightening allowed.  No racing pistons (e.g. Venolia, Ross, Wesco, etc.)
  7. Must use stock, stock length rods for that engine (not interchangeable).
  8. Must use stock crankshaft. Balancing allowed. No mixing and matching components to achieve non-stock engine combinations.
  9. Engines with twin cam, multi-valve factory EFI are allowed, but must have no engine modifications whatsoever.
  10. No Variable valve timing engines (ie. V-Techs).


  1. No porting, must be untouched by any grinder, etc.
  2. Must have stock size valves for the cylinder head.
  3. May polish combustion chamber only.
  4. May change valve springs. 
  5. Must have stock, stock ratio rocker arms.  No roller rockers, exotic pushrods, etc.
  6. May do modifications to allow solid camshaft.
  7. 1500 and smaller pushrod engines may be ported and polished.
  8. Aftermarket replacement heads allowed.  Must be make to make with no porting or polishing and no roller cams.  Must not exceed 12:1 compression and must have a manufacturer casting number.


  1. Must be a stock intake.  Non-exotic.
  2. Absolutely no grinding, polishing, etc.
  3. Must be untouched by grinder, etc.
  4. Maximum 1-1/4” adapter plate (except 1500cc pushrods).


  1. Any stock application carburetor – 1 bbl, 2bbl, or 2x1 bbl. Carb.
  2. Absolutely no exotic or performance carbs (Weber, Solex, etc.).
  3. No modifications other than jet changes and power valve changes.
  4. May remove choke assembly, but not choke horn.
  5. No Barry Grant, Chuck Newton, etc.
  6. Maximum 500 CFM Holley carb allowed.


  1. Must have stock points or stock electronic ignition.
  2. After market coils allowed.
  3. No amplifiers or ignition control devices.
  4. No MSD boxes allowed.


  1. Must have muffler.
  2. Headers allowed.
  3. Must extend behind driver.
  4. Exhaust in the driver’s compartment must be protected by a shield.


  1. Must have stock torque converter.
  2. OEM stock flywheel only, but may be lightened and/or balanced.
  3. 1-1/2” hole must be drilled in dust cover to facilitate tech.
  4. Must have stock pressure plate and clutch disc.
  5. Transmission must be stock and work in all gears.
  6. Must have stock starter.
  7. Bell housing must have a conveyer belt or scatter shield to protect driver.


  1. Ford Pinto and Chevy Chevette may move upper control arm mounts to accommodate camber – other makes and models of cars will be considered for this rule on a per car basis.


Any parts deemed illegal or exotic by techman or promoter, WILL BE CONFISCATED and will become possession of T.M.S. to be sold or auctioned at promoter’s discretion. ALL CARS ARE SUBJECT TO A TEARDOWN AFTER ANY RACE (except the Saturday of a double header). Within 5 minutes of the end of the Mini Stock main, ONLY the registered car owner or driver may protest the engine of any Mini Stock competitor. He must take a written protest form, along with $100.00 CASH to the Pit Boss within 5 minutes or the end of the Mini main. If the protested car refuses to tear down he will automatically lose all his points to date. If the car is tore down and found to be illegal he will lose all his points to date. If the car is tore down and found to be LEGAL he will receive the $100.00 cash. Defining teardown -- The cylinder head will be pulled, as will the intake manifold and header. The stroke and bore will be measured and the valves measured. The ports will be checked for any grinding or illegal machining. The lifters (OHC) will be checked for correct ratio. (THE PROMOTER RESERVES THE RIGHT TO TECH ANY PARTS NOT MENTIONED ABOVE.)

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