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Mod-4 Rules

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COMPETING MODELS:

  1. 1972 to present four-cylinder passenger cars or trucks.

  2. No four-wheel drives.

  3. No rotary engines.

  4. No convertibles.

  5. No mid-engine cars.

  6. No Cosworth engines.

WEIGHTS:

  1. The minimum weight will be 2000 lbs.

  2. Cars with a “cc” over 2000 will run one (1) pound per “cc”.

  3. A maximum of 58% left-hand weight only.

  4. Weights may be adjusted for competition purposes.

ENGINE:

  1. Any 4 cylinder piston engine allowed.

  2. Any modifications or parts that will fit inside the engine are allowed.

  3. The maximum setback allowed for the engine will be six (6) inches measured from the centerline of the upper ball joint.

  4. Dry sump oiling systems are permitted.

CYLINDER HEADS:

  1. Aluminum cylinder heads allowed.

  2. Steel cylinder heads will receive a 100 lb weight break.

INTAKE MANIFOLDS:

  1. Any intake will be allowed.

  2. Grinding polishing, port matching, or any other modifications allowed on the intake manifold. 

  3. A spacer plate may be used under the carburetor with a maximum thickness of two (2) inches.​

 

EXHAUST MANIFOLDS:

  1. Headers allowed.

  2. Exhaust must exit behind the driver either out the side or turn down under the car.

FANS and RADIATORS:

  1. Electric fans may be used

  2. An aftermarket radiator may be used; however, the radiator must remain in stock location.

  3. No anti-freeze is permitted.

CLUTCH and TRANSMISSION:

  1. Bell housing most of the 2-inch inspection hole.

  2. All drive-shafts must be painted white.  And must have two safety straps around the driveshaft, one in the front end one in the rear.

COMPUTER:

  1. MSD type ignition boxes may be used.

  2. Any other aftermarket system must be approved by Wake County Speedway Official.

CARBURETOR:

  1. Any single 2-barrel carburetor.

BODIES:

  1. Aftermarket bodies permitted 2- Inner door panels may be removed.

  • Fabricated dashboards are permitted 

  • All glass must be removed. LEXAN windshield must be installed and secured with support straps, no pop rivets.

  • The battery must be mounted out of the driver’s area in a Steel Container or battery box. The trunk area is the recommended location.

  • Stock steel bodies receive a 50-pound weight break.

  • The rear spoiler will be a maximum of seven (7) inches in height.

STEERING WHEELS:

  1. All steering wheels must be magnetic.

  2. All steering wheels must be equipped with quick-release coupling.

FRAMES and SUSPENSION:

  1. Tubular frames may be used.

  2. Sway bars may run Heim joints instead of end links.

  3. Aftermarket part allowed. 

  4. Stock front clip cars receive a 100-pound weight break.

  5. Rear leaf spring cars receive a 50-pound weight break.

SHOCKS:

  1. Only one shock per wheel.

  2. Coilovers may be used.

  3. Big spring cars will receive a 50-pound weight break.

RIDE HEIGHT:

  1. Minimum ground clearance or ride height will be two (2) inches.

  2. This includes the frame, spoilers, body sheet metal, and side panels.

WHEELS:

  1. Aftermarket steel wheels permitted.

  2. A maximum wheel width of 10 inches.

BRAKES:

  1. Aftermarket brake systems permitted.

  2. Rotors and drums must be magnetic steel.

  3. All brakes must be in working order.

REAR ENDS and DIFFERENTIALS:

  1. Quick change rear ends permitted.

  2. Stock-type rear ends will receive a 100-pound weight break.

  3. Locked differentials permitted.

  4. Magnetic steel axels only.

FUEL SYSTEM:

  1. Fuel cells are mandatory.  Maximum volume of 8 gallons.

  2. Fuel cells must be mounted in the center of the frame rails as far forward as possible. It may be open in the bed area. 

  3. A fuel cell protector bar height minimum of 1½ inches in diameter and a minimum wall thickness of 0.083 inches magnetic steel tubing must be used.

  4. The bar must extend below the frames section behind a fuel cell or the fuel tank.

  5. Fuel-injected cars may use the stock gas tank and must run less than half capacity.  A fuel line for these cars cannot run through the driver’s compartment.

  6. Minimum 8-inch ground clearance for the fuel cell.

SAFETY/ROLL BARS:

  1. Four (4) point cages with curved door bars are required.

  2. Roll bars must be welded and made of a minimum wall thickness of .090 seamless tubing.

  3. Roll bars must be at least 1 ½ inch OD.

  4. The rollbar may be extended through the firewall and loop around the radiator.

  5. Roll bars may be extended to the rear deck also.

  6. A fuel cell protector must be installed behind the fuel cell.

  7. The right side cage must have 4 bars in the door area.

  8. Drivers' door roll bars should have intrusion plates welded to the outside a minimum of 1/8 inch plates.

  9. Refer to the Whelen All American Series rulebook for cage construction guidelines.

SEAT BELTS:

  1. Seat belts must be a 5 point harness type.

  2. Seat belts must be in date in accordance with the manufactures date on the label. The belts may be recertified.

  3. Seat belts must not be mounted to the floor pan.

  4. Seat belts must not cross areas that may cut the belts i.e. not across sheet metal attached to a roll bar.

  5. Seat belts must be replaced if they are worn or the edges are frayed.

SEATS:

  1. Aluminum factory-made racing seats are required. 

  2. Absolutely no homemade seats.

  3. Seats must be mounted in a manner acceptable to Wake County Speedway Officials.

  4. Seats may not be mounted to the floor pan.

WINDOW NETS:

  1. A Wake County Speedway approved window net must be installed on the driver’s side window.

  2. The window net must release from the top and drop down.

  3. Window net bars must be substantial enough to contain the drivers' arms in the event of a rollover.

FIRE EXTINGUISHER:

  1. All trucks must have an onboard fire extinguisher at the race track.

  2. The extinguisher must be mounted so the charge gauge can be checked by Wake County Speedway Officials.

  3. Out-of-date fire extinguishers are not allowed.

ALL RULES ARE SUBJECT TO ADJUSTMENTS BY THE SPEEDWAY COMPETITION DIRECTOR TO ENSURE FAIR COMPETITION!

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