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Southwest Speedway 2019 HOBBY STOCK RULES





No car changes are allowed after the heat race. In the event a car is inoperable PRIOR to the heat race, another car may be used so long as that car has not been already qualified for that night’s feature. The transponder and car number must be transferred to the new car, although the track has discretion to allow exemptions if a situation dictates.

Points will be awarded to the driver. Points and line-ups will follow the current IMCA system in all other aspects. (No more points awarded to teams.)




1. Any American made car with a minimum factory specification of 108 inch wheel base (1/2 inch tolerance), maximum difference ½” from side to side.

2. No vans, trucks, station wagons, or convertibles.

3. Minimum weight with driver: 321 cu. in or less = 3400 pounds, 322 to 367 cu. in. = 3600 pounds, over 367 cu. in. = 3800 pounds.

4. No reinforcing, cutting apart, welding, or modification of anything on the vehicle is allowed except as specified.

5. All glass and flammable materials must be removed.

6. Hood inner structure may be removed. No holes are allowed in the hood. No fresh air access. Hood scoops are allowed if they are not functional. 7. Front wheel wells may be removed.

8. Inner door structure may be removed to allow for door bars only.

9. No removal of rear wheel wells, steel interior panels, or trunk floor (exception for fuel cells, see section K, FUEL CELLS).

10. All doors must be secured shut.

11. Engine must remain in original position.

12. A driveshaft safety loop is required and must be located 6 to 12 inches behind front u-joint. The hoop must be made of minimum 1/4" x 2" steel and, if bolt-in type used, must be mounted with minimum Grade 5 hardware. Loop must be 360 degrees around shaft. NO chain allowed. Driveshaft must be painted white with the car number on the driveshaft in a contrasting color.

13. Rear bumper must be stock mounted and tied to rear fenders with straps.

14. A short piece of 3/8 chain must be bolted through a hole in the bumper and a hole in the frame to prevent the bumper from falling off. This applies to both front and rear bumpers.

15. Any stock front bumper allowed. You may replace your factory shock absorber mount with tubing no larger than 1 3/4" diameter with a .095 wall thickness. Bracing any bumper is permitted using the same material no wider than 48" behind the bumper. Straps from front bumper to fender are allowed and recommended. Tubular bumpers are allowed made of a minimum 1.75 inch by 0.095 inch tube with rounded corners. If a tubular front bumper is used, it must be covered (nosecone, plastic, etc.)

16. Body must match frame and wheel base. All major body panels must be steel.

17. Rub bars may be used on the sides of the car but must be mounted only to the body. They cannot be tied to the roll cage. Rub bar maximum 2" diameter tubing with tapered ends.

18. Sheet, roll plastic, or manufactured nose piece may be used.

19. No enclosed cockpits. 20. All lead or ballast must be painted white, labeled with the car number, and mounted to the car with a minimum of two ½” diameter grade 5 or 8 bolts with washers.




1. A six (6) point roll cage is mandatory: Main cage must consist of minimum 1.75 inch O.D. tubing, with a wall thickness of at least .095 inch. There must be one post by each windshield post and two behind the driver with all four connected at the top with a roof hoop. You must have an angle brace from the driver’s front of the roof hoop to the right rear of the roof hoop. You must have an angle brace running from the upper right corner to the lower left corner behind the driver. The two back bars must run from the top left and top right of the roof hoop to the rear of the car. A protective bar running from the front left cage post forward and down to the frame to protect the driver’s foot area is recommended. A minimum of three inches of clearance from the top of the cage to the top of the driver’s head is required.

2. Minimum of four (4) 3/8" windshield bars.

3. Minimum of three (3) door bars on the left side. Must be 1.75 inch O.D. tubing, with a wall thickness of at least .095 inch.

4. No offset cages.

5. No set back cages.

6. X-bracing under car is allowed and recommended.

7. Steel door plate, 16 gauge minimum thickness, must be securely welded to outside of the door bars on driver’s side. The plate must cover area from top of door bar to rocker panel and from rear main hoop post to 5 inches in front of seat.




1. Each driver must have a fire extinguisher in his/her pit.

2. Aluminum racing seats only. No fiberglass seats. No composite material seats. Seat must be mounted in stock location and not set back. Seat should be attached to the roll cage/seat frame with 3/8 inch minimum diameter grade 8 bolts.

3. A tail light in the rear window is required and must be on at all times the car is on the track.

4. Must have SFI Approved 5-point racing harness. Seat belts must consist of a three inch lap belt and double three inch shoulder belts that release with one mechanism. Two inch to three inch style shoulder belts allowed when used with Frontal Head Restraint (HANS). Belts must be attached with 7/16 or larger diameter grade 8 bolts. Belts must be no more than three years old.

5. A driver’s side window net is mandatory. Window net must be mounted with solid mount at the bottom of the window and latch at the top. Latch must be readily accessible by both driver and safety personnel.

6. Helmet must be a Snell approved full-face helmet. All helmets must have at least SA2010 rating.

7. MUST have an SFI approved fire-resistant driving suit.

8. Neck brace made of a fire-resistant material or a Frontal Head Restraint (HANS) is mandatory.

9. Fire resistant gloves and shoes are mandatory.

10. All holes in firewall and floor pan must be covered with metal.




1. Stock cast iron two barrel intake ONLY. No porting, polishing, or gasket matching.

2. No aluminum intakes. No carburetor adapters or spacer plates.

3. No porting of heads, intake manifolds, or exhaust manifolds.

4. Flat tappet hydraulic camshafts only. No roller cams or roller lifters allowed. No mushroom or step lifters allowed. No machining permitted to install cam or lifters. Must be able to remove lifter from top of lifter galley at any time. No truing of lifter bore.

5. Stock log type manifolds only. No center dump, Vortec, or LT1 exhaust manifolds. No headers. Exhaust must exit under the car and away from the driver.

6. No double hump heads. No Vortec heads. (Casting numbers NOT allowed: 186, 462, 461, 461x, 492, 432, 041, 040, 370, 10239906.) No Ford GT-40 or Mopar “W” race heads allowed.

7. NO roller tip rockers, NO roller rockers.

8. Heads must match engine. For example: 305 heads on 305 block.

9. Stock pistons. No flat-top pistons in 400 cu.in. engine. No domed pistons. Cast piston with 4-value reliefs only. No forged pistons. No Keith Black or any other light weight racing pistons, etc.

10. Piston must sit below deck of block.

11. Heads cannot be angle milled.

12. Stock stroke. Crank must match block. No offset grind. No Scat crankshafts or Scat rotating assemblies.

13. Rods must match block. No lightening, grinding, knife edging or polishing of any type. No bushed or floated rods.

14. Balancing is allowed.

15. Stock two-piece balancer only.

16. No aluminum parts other than stock for that engine. No aluminum water pumps on Chevrolet.

17. Aluminum pulleys allowed.

18. Valve seats may be ground no further then 1/4 inch below top of seat. Valve must match head being used. Maximum size valve will be 2.02” intake and 1.60” exhaust on Chevy heads. Other manufacturers may be subject to approval.

19. Steel non-roller rockers only. No stud girdles. No guide plates. Press fit rocker studs may be replaced with screw in studs. Shouldered style studs allowed. Valley pans allowed. Dodge engines may replace factory non-adjustable rocker arms with factory 273 adjustable rocker arms to permit adjusting valve lash.

20. Valve springs must be stock diameter for heads being used. No helper springs. No beehive springs. No oval shaped spring wire.

21. Any steel, wet sump oil pan allowed. Racing oil pan allowed. Pan will go with claim.

22. 9.5:1 Maximum compression ratio. Will be checked with Katech Whistler Compression Ratio Tester.

23. No intermarriage of engine manufacturer and frame.




1. One 2-barrel carburetor only.

2. No front bowl Holley carburetors.

3. No marine carburetors or intakes.

4. Carburetors must be unaltered OEM, except: booster I.D. may be machined to 0.25 inch, venturi I.D. machined to 1 3/8” (1.375 inch) and throttle bore I.D machined to 1 11/16” (1.6875 inch) on Rochester carburetor. 0.625 inch minimum booster height on Rochester carburetor. Holley jets allowed. All other carburetors may be subject to approval.

5. Choke can be removed but not the air horn.

6. No electric fuel pumps. Mechanical engine driven pumps only.

7. Fuel must be gasoline only. Up to 10% ethanol-enriched gasoline may be used. No alcohol, no nitrous oxide or nitromethane, no nitrous devices allowed. No methane or propylene oxide allowed.

8. Racing gas pedal recommended.




1. Ignition must be either point system or stock electronics (HEI). No super coils. No multiple spark boxes (like MSD).

2. No rev limiters or traction control devices allowed.




1. One Radiator only.

2. Radiator may be aluminum.

3. Radiator must be in stock location.




1. Stock 3-speed automatic transmission only. Must be fully functional with three forward gears and working reverse. No lightening or removal of internal parts allowed.

2. No powerglides allowed. No manual transmissions allowed.

3. Transmission is subject to teardown/protest.

4. Stock diameter torque converter only. (Stock to transmission being used.)

5. No modified torque converters.

6. Posi-traction or welded rear ends are OK. Aftermarket mini spool allowed. No full spools allowed.

7. No intermarriage of rear ends and transmissions.

8. No addition of ballast weight of any kind to the rear end housing.

9. No offset trailing arm bushings allowed. Stock length and style trailing arms and bushings only.




1. The battery must be moved inside the car or to the trunk and be securely fastened. (NO TARP STRAPS). If battery is mounted in the cockpit area, it must be an Absorbed Glass Mat (AGM, dry cell) battery. Wet cell batteries must be covered. (Wet cells allowed in the trunk.)

2. One battery only -- must be 12 volt.




1. Brakes must be factory stock including master cylinder.

2. Drum brakes allowed on rear axle of car only. No drum brakes allowed on the front.

3. All cars must have four working brakes at all times. No shut off valves allowed.

4. Brake pedal must be of stock length for the make and model of car and must be mounted to the stock position on the firewall.

5. No altering of suspension or steering. Steering shaft with u-joints or slip joint is OK. All suspension parts must match frame. Bolt on spindle protectors allowed.

6. Shock absorbers must be mounted on the stock upper and lower mounts. No modifications allowed on shock mounts, and mounts must be in stock locations. No tie rod end, heim end or aluminum shocks allowed. One shock per wheel for a total of four shocks per car. No coil over shocks allowed. No spacers of any kind allowed. Shocks must be steel and non-adjustable. No remote or external canister type of shocks allowed. Shocks must be steel body, one piece or multi-piece allowed. No bulb tops, may have removable bushing on shaft end of body. Bushing holder/eyelet must be fixed to body. No Schrader or bladder style valves allowed. Must use stock type shock ends top and bottom. Front half of shocks can be covered. 7. Springs must be in the stock location and position; stock spring hangers only. Any 5-inch minimum diameter spring allowed front. Rear springs must have pigtails on both ends. Spring cups/spacers allowed in front but must be steel and non-adjustable.

8. The free-standing height on springs must be within one half inch from side to side.

9. Leaf springs must have the same arch, not vary more than one half inch from side to side. Left and right sides must have the same amount of leaves. All the leaves must be the same width and thickness.

10. No rebuildable ball joints allowed.




1. Fuel tanks must be moved into the trunk area. Trunk floor may be gutted for fuel cell BUT no more than

2 inches around cell. If fuel cell protrudes below trunk floor, a fuel cell guard must be in place. This guard will consist of a piece of tubing, minimum of 1 1/2 inches in diameter, 1 inch below the cell and from frame rail to frame rail. The bottom of the fuel cell cannot be lower than the bottom point of the stock frame rail. Cell must be mounted to the roll cage. 2. Maximum capacity of fuel tanks not to exceed 10 gallons. Fuel CELLS may be larger.

3. There must be a firewall between the driver and the fuel tank or fuel cell.

4. Fuel tank must be securely mounted using a minimum of two (2) 2” steel straps.

5. If a fuel cell is used, it must be in a metal container.

6. Fuel cells must have flapper valve installed on filler neck or sealed cap to prevent fuel spillage in the event of a rollover. Vent must have a check valve or be plumbed so that it vents lower than the bottom of the cell and be securely fastened.




1. DOT tires must be maximum 8" tread width measured with a tape measure from shoulder to shoulder, NOT manufacturers specification. This will be up to the tech inspector's discretion. Must be a passenger series tire with P255/60R15 being the largest tire allowed. IMCA G-60, WISSOTA H-40 or WISSOTA 35 (series) tires will be allowed. No defacing of tires. Grooving, grinding and siping is allowed. The same tire types must be run on all four corners of the car. No mixing of tires will be allowed.

2. 14" or 15" Stock steel wheels, white/chrome spoke or modular wheels. Racing type wheels will be allowed but must weigh a minimum of 19 pounds. All wheels (racing or not) will have a maximum wheel width of 8" with an offset of 2”, 3” or 4", plus or minus 1/2". (This measurement will be from the inside bead area of the wheel to the bolt plate with a tolerance of + or – ½”) NO light weight (less than 19 LBS) racing type wheels allowed.

3. NO Wheel Spacers.

4. Beadlocks are NOT allowed.

5. Must have one-inch OD lug nuts. Steel only, no aluminum. Five-eighths inch wheel studs recommended.




This class is designed for stock street cars only. NO high performance or racing parts allowed on this car. Suspension, engine and drive train must remain STOCK. Any areas not covered in the above rules shall be left up to the discretion of the officials. If in doubt -- ASK. We will uphold the intent of the rules.




Cars must be neatly numbered using numbers integers from 1 through 99. Numbers must be at least 18” high and 10” wide with a body of 3”. Numbers must be displayed on the door on both sides of the car and the roof. Six inch tall car numbers must be displayed on the front and rear of the car. All numbers must be of contrasting color to the car. Do not incorporate graphics into your number. Simple block numbers using the above dimensions and of a contrasting color are the easiest to read. Do NOT paint number on the rear quarter panels. Do NOT use shiny reflective or prismatic type decals.




1. All cars will be kept neat appearing. Bodywork hanging off cars and/or sharp edges will not be allowed.

2. Minor changes to the body rules may be allowed. For instance, a front valance or a rear spoiler may be allowed that enhances the appearance of the car as long as it is deemed nonfunctional. This will be left to the discretion of the tech inspectors.








All race cars competing in the feature event are subject to being protested. Any driver competing in the feature event may protest providing his or her race car meets the minimum weight and is deemed otherwise legal by the tech inspector. Intent to protest must be filed with a track official prior to the start of the feature race and the required protest fee must be tendered at this time. The protest fee shall be $100 for the top end and $200 for the bottom end or $300 for both. If after tear down, the engine is found to be legal, 75% of the protest fee will go to the protested driver and 25% of the fee will be retained by the track. If after tear down, the engine is found to be illegal, 75% of the protest fee will be returned to the driver who protested and 25% will be retained by the track.




Immediately following the completion of the feature race, a track official will notify the driver of the protested race car that his/her race car has been protested. The protested driver shall then proceed directly to the claim area where he/she will receive further instructions as to where the tear down will take place. A track official will be assigned to stay with the protested car until the tear down is completed.




Only the driver may protest. A driver may only protest one engine per race. The tech inspector has the final word on the legality of the race cars involved in the protest. No person shall prevent or interfere with the protest procedure. Only the driver and two pitmen from the protested car may be present at the tear down. Only the driver and one pitman from the protesting car may be present at the tear down. The track will designate appropriate track officials to be present at the tear down.




If an engine is found to be illegal, the driver of the protested car will forfeit all points and money earned for the event at which the engine was protested and may serve up to a 2-event suspension. The 2-event suspension applies to both car and driver. Refusal of a protest will result in the same penalties as above. In the case of a protest refusal, the protest fee will be returned to the driver who protested. A second protest refusal by the same driver in the same racing season shall result in loss of all points and money earned for the event at which the engine was protested, a 4-event suspension for both car and driver, and loss of all points earned year to date.




The fee to protest a transmission will be $100. The Eligibility, Procedure, Special Provisions and Penalties will be the same as the Engine Protest Rule.




There will be an engine claim of $200 plus exchange. The claim must be made within five minutes of the end of the feature event. The claim can only be made by the driver and the claim fee must be in US currency. The claiming driver’s engine must be in good, sound running order according to the track officials. In order to claim, a driver must be in the top 8 finishers, on the same lap as the winner, and must not have been involved in causing a yellow during the feature event. The cars in the last two (2) places are ineligible to claim. The car whose driver is claiming must meet all rules and must weigh after the feature. The claim rule will not be in effect on first TWO track point nights. Following the second night, no driver may claim unless they have competed at ALL previous weekly sanctioned track point events. Engine claim rule will not be in effect on season championship night. Exception is: If a driver is claimed at any weekly point event, he may claim at any following event at that track without needing perfect attendance. Driver can only claim one engine during current calendar year. Exception is: After any driver has had more than one engine claimed, they are eligible to claim as many engines as they have had claimed. Driver allowed only one claim per event, regardless of outcome. No driver may claim the same driver more than once during current calendar year. Driver being claimed is subject to only one claim per event. The claim includes everything except: carburetor, ignition, exhaust manifolds, starter, water pump, fan belts, and pulleys.


The refusal of a claim will result in a 30 day suspension for both car and driver and the loss of all points and money earned that night, as well as all points year to date and a $250 fine. Suspension time must be served, and fines must be paid before the driver is allowed to race again.