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Street Stock Rules



TERMS: Stock OEM replacement means that the item/part must have been a standard item/part on the MAKE and MODEL of the vehicle being driven as a race car. Just because a part is manufactured by the company that manufactured the vehicle does NOT mean the part is legal. The part must have been available on the specific vehicle being used as a racecar. Stock OEM replacement direct fit, direct replacement parts must meet size/weight/material requirements as if factory produced. No Modifications. Factory Stock/Production or Factory Produced means manufactured by the company who produced the vehicle being used a race car and those manufactured for the year/make/model/of the race car. No Aftermarket parts allowed.

PREFACE: Any participant who refuses to allow tech officials to inspect their car will be subject to the following – disqualification from the event, lose of all points, and prize money from that event. For handicap purposes you will be credited with a feature win. Any participant found to be illegal and disqualified from an event will not receive points or prize money for that event. If found illegal on a double feature night, the car will be declared illegal for both events and will not receive any points or prize money for either event. For handicap purposes you will be credited with a win for both events. Engine violations or technical issues that are deemed illegal – You will be disqualified from the event, lose of all points and prize money from that event and may lose all accumulated points to date. Humberstone Speedway reserves the right to confiscate any illegal components at any time. Humberstone Speedway reserves the right to alter or amend these rules at any time in the interests of safety, cost or fair competition. The safety of each race car and all equipment is the complete responsibility of the driver/owner and the driver/owner acknowledges this responsibility by participating in any racing activity at Humberstone Speedway.


1. STREET STOCK COMPETING MODELS a. Competition is open to all North American made steel bodied passenger cars from 1969 and newer. b. Minimum factory wheelbase must be 106″ c. No Jeeps, 4WD, SUV, station wagons, compacts, convertibles, sunroofs, T-tops or trucks allowed. No front wheel drive or fuel injected vehicles allowed. d. Cars may be disqualified if they are considered too battered or unsafe.

2. APPEARANCE a. Cars must be neatly painted with numbers at least 18 inches tall on side, doors and roof (facing the grandstand)

3. AIR CLEANERS a. Aftermarket air cleaners may be used. b. Air cleaners may not extend beyond the hood.

4. AIR FILTER a. K & N style filters are allowed. b. No special air cleaner top or bottom allowed that directs air into the carburetor. c. No plastic air cleaner tops or bottoms – must be metal only. d. No carburetor inserts to direct air into the carburetor allowed. e. No air boxes, hoses or any device that directs air into the air cleaner allowed.

5. BATTERY a. It is recommended that the battery be mounted under the hood and must be mounted securely in a spill proof container and must be securely fastened. b. Positive terminal end to be insulated to prevent shorting – use of rubber suggested.

6. BODY a. Body must retain Factory Stock appearance, location and dimensions. b. The body panels must be steel (and are available for purchase aftermarket) and must remain in stock location for the car’s make and model. Body Panels must not be lower than the frame rail. c. Altered bodylines will be significant reason for disqualification. d. Bodies must be attached and mounted in original stock factory location. e. No off setting bodies – they must be centered on the chassis. f. The body may not be lowered on the frame. g. Windshield pillars and windshield angle must remain stock appearing. h. Headlights, parking and taillights must be removed and must be neatly covered.

7. BODY MOUNTS a. Bracing must be welded or bolted to a minimum 2 (two) locations on the frame and two locations on the body.

8. BUMPERS a. Stock front and rear bumpers for the car’s make, model and year and must remain in stock position. b. A bar may be mounted inside the bumper at 19″ from the center to the ground. c. All bumpers must be rolled in and be securely fastened in place. d. Bumper shock brackets must be welded and or bolted. e. Plastic front nose is allowed on metric GM cars. f. Aftermarket plastic or rubber tailpieces are allowed provided they are stock OEM replacement.

9. BRAKES a. All cars must have OEM working brakes on all four (4) corners at all times. b. No shut-off valves on any brake line are permitted. c. No rear disc brakes allowed.

10. DOORS a. All doors must be welded or bolted shut. b. An approved window net is mandatory with a quick-release latch. DRIVE TRAIN REQUIREMENTS:

11. TRANSMISSION a. Only stock manufactured automatic three speed transmissions are permitted – No alterations. b. Transmission must have all operational forward and reverse gears. c. Functional OEM stock unaltered V8 torque converters are required. d. Transmission coolers are allowed and must be mounted in engine compartment.

12. DRIVESHAFT a. Drive shaft must be steel OEM type. b. Drive shaft must be painted white. c. One front 360 degree drive shaft hoop (mounted towards front half of driveshaft) made of 1″ x .095” tubing is mandatory.

13. REAR ENDS a. Rear end must be same as make, model, of chassis being used. b. Rear end may be locked by welding spiders or using steel mini-spool. c. Any gears can be used. d. Racing wheel studs and 1″ hex wheel nuts are mandatory e. Aftermarket control arms (with stock length) are allowed.

14. ELECTRICAL SYSTEM a. The self starter must be in working order and located in stock position. b. Only standard factory OEM type production starters are permitted. c. All cars must start under their own power. d. Stock OEM HEI distributor. No after market coils or modules allowed.

15. EXHAUST SYSTEM a. Unaltered stock cast iron exhaust manifold or factory built steel street style headers are permitted. b. Primary pipes must be a maximum of 1-5/8″. c. No Center dump manifolds allowed. d. Mufflers are mandatory – maximum exhaust pipe is 2-1/2″ diameter. e. Mufflers must be unaltered OEM or unaltered “California Turbo” type muffler. f. No round glass type mufflers are permitted. g. The complete exhaust system must remain under the car and exit behind the driver. h. Maximum exhaust pipe diameter 3.00 with no headers. i. Neither H pipes or two in one exhaust are allowed.

16. FIREWALLS a. Front and rear firewalls must remain in original location. b. Stock mounted brake pedals must be mounted in stock location however pedals may be extended. c. Sheet metal may be added to repair firewall mounted in original location. d. Floorboards must be stock appearing and match up to original driveshaft tunnel. Floor may be replaced with a minimum 16 gauge steel. Right side may be raised 12” for exhaust clearance to the top of the driveshaft tunnel and level across. e. Rust holes must be patched. f. Rear firewall must be completely sealed off from driver’s compartment. Must use 18 Gauge Steel minimum. No aluminum. g. Rear firewall may start no further forward than 20″ in front of the rear axle centre line at floor boards and continue upwards on a straight plane to the stock upper rear window ledge.

17. FUEL a. PUMP GAS ONLY – Delta Sonic Pump Gas (CAM2) is not allowed. No additives allowed. No Aviation Fuel

18. FUEL CELL a. Stock gas tank must be removed and replaced with a mandatory fuel cell. b. Fuel cell shall be securely mounted in the trunk area with a minimum of two straps of 1/8″ x 1″ steel. c. Fuel cell to be no lower than the lowest part of the frame section or must be fully protected by a minimum of 1-1/2″ tube. d. if fuel cell is not fully enclosed to the outside it must be in a container made of a minimum 20 gauge steel. e. No stock location tanks allowed. f. No aluminum tanks allowed. g. All caps, fittings and lines must be secure, leak proof and of high quality. If mounting through the driver cockpit, it is highly recommended to mount fuel line and a fuel shut off within the driver reach. Also mark ON / OFF if fuel shut off is used. If mounted under the floor board (mount securely and use steel fuel line tubing only – NO CHEAP NEOPRENE hose under the floor board) h. Fuel line from trunk to engine must be one continuous line securely fastened under floorboard & attached to frame. i. Trunk must have to be opened to refuel. j. Fuel cell filler neck must be grounded to the car. k. No sloppy installations.

19. FUEL PUMPS a. One mechanical fuel pump only b. No electric or belt driven fuel pumps allowed.


20. FRAMES a. All frames must retain all Factory Stock specifications and dimensions for make and model from front to rear. b. Rusted areas may be reinforced for safety. c. Unibody cars may tie sub frames together with straight ties only. d. Sub frames may be tied together but must be symmetrical to the centerline of the car. e. Rear frame rails may be reinforced but mounting hardware for springs must remain in exact factory stock location.

21. GLASS & TRIM a. All glass and plastic must be removed. This includes all chrome, lights, mirrors, reflectors and trim. b. Glass inside each door panel must be removed.

22. HOOD & TRUNK a. All hoods and trunks must be in stock position and properly sealed from drivers compartment. b. All hoods and trunks must be securely fastened. c. No Holes in hood for air cleaner. d. A 1-1/2 inch deep hood scoop by 20 inch maximum resembling a Camaro injection style hood is allowed. This is to cover the air filter only and must be sealed front and back. Start of hood scoop has to be maximum 20 inches in front of carburetor centerline

23. INTERIOR a. All knobs, handles, decks, unnecessary upholstery and seats must be removed. b. No rear view mirrors are allowed inside or outside of the car.

24. RADIATOR a. Radiators must be in stock location only. b. Aluminum radiators allowed provided they are bolt in replacement style. c. Mechanical steel fan blade (water pump driven) with an auxiliary electric fan is allowed as an option for cooling purposes only.

25. RADIO/TRANSPONDER a. One way radio RACEceiver/scanner is mandatory. Frequency is 454.000. Transponder is also mandatory. You may purchase your own, or rent from the Speedway. It is recommended that you purchase your own.

26. ROLL CAGE a. No offset cages. b. A roll cage is mandatory and must consist of a minimum six point roll cage with approved driver protection. c. Roll cages must be welded directly to the frame. d. Roll cages must be constructed of steel tubing 1-1/2″ o.d. x .120″ wall thickness or 1-3/4″ o.d. x .095 wall thickness. e. Three (3) horizontal bars minimum running between the front and rear upright bracing are required on the driver’s side and must bow outward. (not including the frame) f. Passenger side must have a minimum of (3) horizontal bars running between front and rear upright or a X with a top straight bar not including the frame g. All unibody vehicles WITHOUT frames must use the “sandwich” method when securing the cage into the vehicle. h. The bottom of each upright must be welded to a 6″ x 6″ x 1/4″ steel plate and using a minimum of four (4) 1/2″ inch bolts bolted through the floorboard to another 6″ x 6″ x 1/4″ steel plate on the underside of the car. i. Front centre windshield post of minimum 1-1/4″ o.d. x .120” wall steel mandatory. j. Upper roll cage must have centre roof bar of 1-3/4″ o.d. x .095 wall or 1-1/2″ o.d. x .120 ” wall steel minimum. k. Main roll bar must be symmetrical to the driveshaft. l. Main roll bars in driver’s immediate area must be padded.

27. RUB RAILS a. One rub rail allowed on each side and must be 1″ by 2″ rectangular tubing mounted tight to the door panel only. b. Each rub rail must have ends beveled with no sharp edges.

28. SAFETY a. Driver must wear an SFI rated or greater fire retardant racing suit. b. Driver must wear a proper fitting full faced Snell-rated SA2000, SA 2005, or SA 2010 helmet. c. Fire proof gloves and footwear recommended. d. Neck collar is recommended. e. Helmet must be worn at all times when driver is in vehicle. f. All cars will be required to have in their pit area, a fire extinguisher capable of extinguishing gas and oil fires. It must be visible to tech officials and all crew members. All crewmembers must be made aware of its location and must be knowledgeable in the use of the fire extinguisher

29. SEAT a. Seat must be an aluminum high back racing seat. No fiberglass allowed. b. Seat must be securely fastened to frame and cage in six spots. Four (4) on the bottom and two (2) on seat back. c. No floorboard installations allowed. d. The seat must be positioned to the left of the centre of the car. e. All bars and sharp contact areas around driver must be padded.

30. SEAT BELTS a. One 3″ inch wide SFI –approved lap, two belts over the shoulder and one submarine strap mandatory. b. Both ends of lap belts must be securely fastened to the frame and roll cage with high quality bolts, not less than 7/16 inch in diameter. 1/2″ inch recommended. c. No frayed or torn belts. d. It is recommended that seatbelts are no more than 3 years old.

31. SHOCKS a. One stock appearing steel shock mounted in stock location per wheel. b. Pricing not to exceed $100.00 Canadian per shock.

32. STEERING COLUMN a. Steering column must be in original position for make and model. Stock style collapsible steering column. b. Steering wheel quickener will be allowed.

33. STEERING WHEEL a. The steering wheel center must be padded. b. Minimum size of steering wheel is 12″ diameter.

34. SUSPENSION a. Front and rear suspension must be stock dimensions. b. The use of twist in ties or rubber spacers is allowed between the coils. Nothing allowed above or below. c. The use of aftermarket bushings is allowed. d. Stock replacement upper control arms are allowed. The use of Aftermarket Upper Control Arms is allowed, providing they meet stock requirements. e. Rear Control arms may be fabricated to stock dimensions or stock arms may be reinforced.

35. TIRES a. Optional Engine Rule or GM Crate may use Hoosier 8″spec tires. b. Optional Tire: American Racer “Stocker tires” will be allowed. Tire Size Tread Width Section Width Approx Diameter Approx Circ. 26.5/8.0-15DT 9.0 10.8 26.7 84.0 27.5/8.0-15DT 9.0 11.2 27.4 86.0 c. Stock engine maximum tire size P235 with a max 8″ tread. DOT numbers and tire stampings must be visible. d. No snow tires allowed. e. Minimum recommended tire pressure 10 PSI. f. Grooving and sipping allowed.

36. WHEELS a. Steel racing type wheels allowed. b. Maximum width of eight (8) inches. c. Minimum Three (3) inch and Four inch maximum offsets (backsets) allowed. d. 1/2 inch studs minimum are mandatory on all four wheels. e. Must use one (1) inch hex wheel nuts and with (5) on each wheel. (20 wheel nuts per car) f. A wheel spacer up to a 1/2″ on right rear is allowed. g. An optional bead lock will be allowed on the right rear only, lexan cover or foam mud plug only will be allowed. Only foam allowed on right front.

37. TOW HOOKS a. Front and rear tow hooks are required.

38. WATERPUMPS a. OEM replacement water pumps only allowed. b. The use of aftermarket pulleys will be allowed to assist over heating.

39. WINDSHIELD a. All glass must be removed. b. Windshield must be replaced with full screening from door post to door post.1″ square maximum.

40. WEIGHT a. All cars must weigh a minimum of 3000 pounds after the event with the driver. b. Any added weight must be securely fastened with two minimum 1/2″ diameter grade 8 bolts. c. No added weight allowed in the driver compartment. d. Added weight must be painted white with the car number painted, engraved or stamped on each piece. e. It is recommended that extra roll cage and driver protection be considered for reaching legal weight. f. Rear Weight % for rear leaf springs cars maximum 47%. 4 coil spring cars maximum 49%

41. WINDOW NETS a. Ribbon style window nets are mandatory on driver’s side of car. b. Window net to be mounted so latch is at top front of window.

42. SPEC. ENGINE RULE: NOTE: The engine owner will be responsible for any and all costs incurred in the tech inspection of this engine. a. All engine blocks must be standard factory production passenger block mounted in stock location. b. Engine block and component parts must retain all standard stock external and internal dimensions. c. No aftermarket or aluminum blocks. d. Zero deck allowed on blocks with maximum .060 overbore allowed. e. Internal polishing of the engine is not permitted. f. Chevrolet 350 c.i., Ford 351 c.i., Chrysler 360 c.i. allowed. g. Stock hardware on engines only.

42.1 CARBURETOR a. Holley R4412 that must remain box stock except for the following – choke may be removed, throttle shaft may be welded, jets and power valves may be changed. b. Throttle shafts must remain standard and must not be thinned, cut or altered. No modifications. c. Carburetor must be mounted parallel to intake. d. Track Officials reserve the right to and will exchange any competitor’s carburetor at any time. e. One BRP 377 adapter only. f. Two .030 gaskets only. g. No air induction plastic inserts or other devices to direct air to intake.

42.2 CAMSHAFT & TIMING CHAIN a. Hydraulic camshaft only. Not to exceed .450 lift on intake and exhaust with stock diameter lifts. b. No roller cams, no mushroom cams allowed. c. No gear or belt driven cams. d. Timing chain and gear may be of a roller type or OEM replacement chain and gear.

42.3 CRANKSHAFT & HARMONIC BALANCER a. Only factory production cast iron crankshafts with no other modifications of any kind except minimum .030 under size. b. Part # 3932442 or Part # 14088526. c. Drilling for balancing only. d. Must remain stock stroke. e. Knife-edging, polishing, undercutting, and lightening are not permitted. No modifications. f. Factory production or OEM replacement harmonic balancers are permitted – i.e. Chev. balancer w/Chev. Engine g. No Solid balancers.

42.4 CYLINDER HEAD a. All cylinder heads must be factory production stock cast iron 882 head only. b. Identification and part numbers must remain on the part being used with no alteration. c. Any attempt to alter, change or eliminate part numbers will result in that part’s ineligibility. d. Maximum intake port of 160 c.c. and maximum exhaust port of 60 c.c. with minimum 74 c.c. combustion chamber. e. No internal grinding except valve seats. All cutting in reference to the valve job must be centered off of the centerline of the valve guide. Upon completion of the valve job, the bowl area under the valve seat down to the bottom of the valve guide must still be the same configuration as far as shape and size as it was from the manufacturer. Must remain same configuration. f. No work below the valves. g. Screw in studs and poly locks allowed. h. Maximum valve size Intake 1.94 and Exhaust 1.50. i. Stainless steel exhaust valves allowed. No neck down valves. No titanium valves. j. No bronze guides, but bronze liners allowed. k. Minimum head gasket thickness .040’’ l. Stock diameter single valve springs and retainers only. m. Valve spring maximum diameter of 1.260 with a seat pressure of 120 pounds. n. Minimum installed height allowed will be 1.70 with a maximum of 1.750 o. No dual valve springs. p. Guide plates and screw in studs allowed.

42.5 INTAKE MANIFOLD a. Intake must be as cast box stock with no modifications or grinding. b. Manufacturers and part numbers that are legal are as follows: c. Weiand X- Celerator, Chevrolet # 7547, Ford # 7515, Chrysler # 7545, Edelbrock Torker II, Chevrolet # 5001, Ford # 5021, Chrysler # 5076

42.6 OIL PAN a. Any factory production or OEM replacement steel oil pan. b. No oil coolers allowed. c. No accusumps or external oil pumps allowed. d. Claimer style, kicked out steel oil pans are allowed.

42.7 PISTONS & RODS a. Factory production unaltered replacement three ring, four eyebrow flat top cast aluminum pistons allowed. No modifications. b. Only factory production or OEM standard steel piston pins may be used. c. Only Factory production steel connecting rods permitted. d. All rods must maintain the standard stock rod length for engine block used. e. No Oldsmobile Rods. f. No modifications of any kind.

42.8 PUSH RODS a. Stock length and diameter push rods. b. Chev 350 1.250 diameter spring with installed height of 1.70 c. Ford 351 1.50 diameter spring with installed height of 1.82 d. Chrysler 360 1.500 diameter spring with installed height of 1.65

42.9 ROCKER ARMS a. 1.5 stamped steel rockers only. b. No roller tip or roller rockers.

42.10 STOCK ENGINE a. Stock unaltered engine and transmission combination must be within chassis as a factory item, including all engine accessories except air filters, valve covers and oil pan. b. Engine block must be standard production and have stock external and internal measurements except for maximum .030 overbore. c. Chevrolet engine up to 350 c.i. with .030 overbore allowed. All other engine makes – no cubic inch limit. d. Engine must match make and model of car used. e. Engine must be in stock location and retain stock crank height. f. Maximum one (1) stock unaltered 2 barrel carburetor. 1-3/8″ inch venturi size maximum allowed and up to 1-11/16 ” throttle plate. g. Stock cast iron intake only. h. All engines must use cast, stock, OEM flat top pistons with four eyebrows and full skirt. Stock OEM production rods, crank and block. i. Cylinder heads and two barrel intake must be stock production cast iron. No porting, polishing or grinding. No work below valve seats. No Chevrolet angle plug heads. j. OEM stock valves only maximum 1.94 intake and 1.50 exhaust. Any hydraulic camshaft may be used. Maximum lift is .390 intake and .410 exhaust at the valve. Hydraulic valve lifters may be used. k. No roller cams, roller lifters or tappets allowed. l. Maximum compression ratio is 9:1. Compression will be checked with the Whistler Compression Ratio Gauge.

43. 2012 “OPTIONAL” GM 88958602 CRATE ENGINE NOTE: The engine owner will be responsible for any and all costs incurred in the tech inspection of this engine. a. This engine is not required equipment for our Street Stocks, but is presented as a cost saving alternative engine. b. GM Part # 88958602. c. With this engine you must use a Holley R4412 – 2 barrel carburetor (same as spec engine) with a BRP377 adapter. d. Flywheel/flex plate must remain stock. e. Stock HEI Distributor only. f. Uses of racing fuel or fuel additives are not allowed. Pump Gas only. Delta Sonic Pump Gas (CAM2) is not allowed. No Aviation fuel. g. Engine work on your GM Crate engine must be done through an authorized DIRTcar authorized repair shop only. For more information on repair procedures for your Crate Engine, please refer to the DIRTcar Sportsman Rule Book. h. If there is found to be any tampering of any kind with any GM Crate Engine, that engine will automatically become the sole property of Humberstone Speedway. The engine owner will not have any claims against Humberstone Speedway or its employees, sponsors, or any parties involved with Humberstone Speedway as a result of engine tampering. It is further stated that tampering with any Humberstone Speedway GM Crate Engine will also result in the loss of any accumulated points for the driver. Car owner and driver may also be removed from competing in any further events. i. Humberstone Speedway has the right to claim any engine at retail price as sold by a dealer or simply replace it with a new or rebuilt engine. j. Engines may be removed at anytime at the discretion of Humberstone Speedway Tech Officials for further inspection or dyno testing. PARTICIPANT MUST BE A CURRENT HUMBERSTONE SPEEDWAY WEEKLY RACING SERIES MEMBER DRIVER AND HAVE ATTENDANCE OF 75% OR GREATER DURING THE SEASON TO BE ELIGIBLEFOR ANY AWARDS OR POINT MONEY THAT MAY BE AVAILABLE



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