MODIFIED RULES 

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Mufflers are mandatory and must be of closed end type. No open exhaust baffle pipes allowed. 100 decibel maximum. Any car losing mufflers will forfeit points and prize monies for that night.

ROLL CAGES

1. Must consist of a continuous hoop not less than 1.5 inches outside diameter, and must have a wall thickness of at least .095 inches.
2. Must be frame mounted in at least six (6) places.
3. Must consist of a configuration of front and rear hoops connected by tubing on the sides, or side hoops. Drivers head must not protrude above cage with helmet on and strapped in drivers seat. Roll cage must be securely supported and braced.
4. Low carbon, mild steel D.O.M. tubing is recommended. No brazing or soldering allowed.
5. Protection of feet is mandatory. Bar across back of engine with vertical bars and rub rails, or similar protection.
6. No brace bars forward of cage may be higher than stock hood height.
7. Chassis must have drive shaft hoop.
8. Driver doors must be as parallel with the ground as possible, and located and perpendicular to the driver so as to provide maximum protection for driver, but without causing undue difficulty in getting into or out of vehicle. Door bars must be .095 inch thickness; must have a minimum of (3) three bars at least 1 1/2 inch in diameter. The door bars must be welded to the front and rear of the roll cage.
9. No brazing or soldering allowed on any of the chassis/frame components.
10. Floor pans with a minimum of 20 gauge steel; of minimum 1/8 inch thick aluminum plate may be used
11. No brace bars forward of a cage may be higher than stock hood height.

BRAKES

1. Must be equipped with operational four-wheel braking system.
2. No drilling of brake rotors or calipers.
3. Rotors may be re-drilled for different bolt pattern or larger studs.
4. No altering of brake rotors or calipers.
5. Rotors and calipers must be O.E.M

EXHAUST SYSTEM

1. Exhaust systems must be mounted in such a way to direct spent gases away from areas of possible spillage of fuels. Headers must be pointed away from ground. No more than 1/2" clearance surrounding header pipe when directed through firewall on driver's side.
2. Mufflers are MANDATORY.

ENGINES

1. Any American make may be used.
2. Rear of engine, bell housing mounting flange surface, must be mounted at least 72 inches forward from the center line of the rear axle.
3. Engine offset must be kept within 2 inches of the center line of the front cross member.
4. Minimum engine height is eleven (11) inches from the ground to the front center of the crankshaft.
5. All engines used in competition must be able to be used in a conventional passenger car without alterations.
6. Engine motor mount locations can not be removed or altered. Castings and fittings must not be altered.
7. No machine work may be done on the outside of engine, or on the front or rear of the camshaft.
8. No dry sump systems are allowed. Wet system in engine must be operative.
9. Engine cooling system may be modified.
10. Engine block must be steel.
11. Exhaust system must be mounted in such a way as to direct spent gases away from the cockpit of vehicle, and away from areas of possible fuel spillage.
12. Battery type ignitions only. NO magnetos allowed. Maximum of one (1) ignition system and / or multiple spark discharge box allowed.

FUEL SYSTEM

1. One 2 barrel or one 4 barrel carburetor only.
2. Engine must be normally aspirated; no type of fuel injection allowed.
3. No electric fuel pumps or fuel systems of any type.
4. Racing fuel cells are required and must be mounted by at least two steel straps, no less than two (2) inches wide x 1/8 thick, all the way around the cell. The use of 1"x 1" x .065 wall sq. tubing is recommended to be used. Using two bars around the top, bottom, and sides of the fuel cell. All fuel cells must be mounted securely to the frame. Fuel cells must be enclosed completely in a steel container, mounted behind rear axle only, and must also be protected in rear by roll cage tubing mounted securely to the frame. * No part of fuel cell should be lower than the protective tubing. Protective tubing should be no wider than 6 inches on both sides of fuel cell. Fuel cells must have check valves, and bladders are highly recommended.
5. Fuel cells are limited to 32 gallon maximum capacity. Fuel cells with fuel pickup located in the top of cell is highly recommended.
6. Fuel may be either gasoline or alcohol. NO nitrous oxide. NO additives of any kind.

KILL SWITCH / BATTERY

1. A kill switch is required. Switch must be clearly marked and located within easy reach of the driver, and safety crews must be able to reach switch from standing outside the car.
2. All cars must have a battery. Battery must be securely mounted. Battery cannot be mounted inside drivers’ compartment.

FRAMES/SUSPENSION/STEERING

1. Factory production complete, full, 1950 or newer parallel American passenger car frames only. Frames may be cut in rear only at a point not further than 36", both sides, from center of rear end housing. No front clips or tube type allowed.
2. Frames may not be widened or narrowed and must be able to support roll cage on both sides. Frame must be full and complete on both sides. Front cross member may be notched for radiator clearance only. Minimum frame height, and body height, must be four (4) inches from the ground.
3. No Jeep, Bronco, (etc.) or 4-wheel drive frames allowed. No sports car frames allowed. No front wheel drive frames allowed
4. Minimum wheelbase is 108", both sides. Maximum wheel base is 112" NO TOLERANCE.
5. Front suspension and steering must be O.E.M. and be in stock location, and must be replaceable by stock part from same type suspension. Stock passenger car spindles only. No fabricated spindles. May use steel bushings in lower control arms.
6. Tube type upper control arms are allowed and can be moved. Cross bar for upper control arm may be steel or aluminum.
7. Lower A-frames cannot be altered or moved. Approved after-market lower control arms are legal but must remain in factory location. Stock mounting positions and lengths must meet OEM specifications. (Outer, Inner, Spring and Ball Joint locations)
8. No center steering. In cockpit steering may be modified to drivers taste, but must remain on the left side of car.
9. No rack and pinion steering. Steering box must be O.E.M. Steering box must remain within original bolt pattern of frame used.
10. O.E.M. Tie rod ends and adjustment sleeves may be replaced by a minimum .625 inch (5/8") rod end (heim joint) and steel or aluminum tube.
11. Rear of frame may be altered to accept leaf or coil springs. Any coil spring on car must be at least 4 1/2 inches outside diameter. Coil springs must be steel. Leaf springs may be steel or composite type. Lowering blocks, rear spring shackles, and rear end drive bars may be steel or aluminum only. No torsion bars allowed in rear.
12. No hydraulic, ratchet, or electric weight jacking devises allowed anywhere in or on the car.
13. One shock per wheel only (Dummy shock allowed on LEFT rear ONLY). Additional shocks in other locations permissible. No Aluminum shocks are allowed. No remote reservoir shocks allowed.
14. No aluminum, fiberglass, or composite suspension, steering, or rear end parts allowed, except where noted in these rules.
15. No coils over shocks are permitted on front of car. No homemade coil overs are allowed – no exceptions. Steel coil-over eliminators or steel/aluminum coil-over kits allowed-must conform to shock and spring rules. (Rear only) (5 inch spring).
16. No covers on springs, shocks, etc. allowed. With the exception, of a small bellows type shaft cover for a coil over eliminator and / or pull / push bar assembly, for maintenance purposes only. Shaft covers are subject to NARA Battle of the Bluegrass Open Wheel Modified officials’ approval, and are subject to removal.

TIRES /WHEELS

1. The following tires compounds are the only tire compounds legal: 

   Hoosier 26.5/8.0-15 - RC2 (A40), RC6 (H40)
               27.5/8.0-15 - RC2 (A40), RC6 (H40)
               Note: RC4 (D40) are no longer legal

    

2. No grooving of tires allowed. Siping is allowed.
3. No tire softeners or conditioners.
4. Hoops for inspection must pass over tire freely.
5. Eight (8) inch steel wheels only. One (1) inch tolerance for beadlocks.
6. Bead locking devices allowed on the right-side (Right Front & Right Rear) wheels only.
7. Any mud plug other than foam must be securely mounted to the wheel.
8. Aluminum wheel spacers are allowed.  Aluminum wheel spacers are allowed.

REAR ENDS

1. Any American made passenger car or truck rear end is allowed. Optional floater type rear ends allowed.
2. Steel-tube Quick change rear ends are allowed.
3. Steel axle tubes ONLY. No aluminum birdcages.

 

TRANSMISSIONS

1. Must have neutral and working forward and reverse. Must be able to go forward and backward with engine running. No in/out boxes. Bert, Brinn or automatic allowed.

WEIGHTS / CAR WEIGHT

 

1. A minimum weight limit of 2400lbs will be in effect at all sanctioned events.
2. ALL added weights must be painted white with the car number on the weight. Each car will be inspected for proper mounting and identification. ANY driver loosing a weight will be disqualified for the remainder of the night if he looses a weight and it is identified as coming from his car.
3. CARS MUST GO DIRECTLY TO SCALES AFTER RACE AND GET IN LINE TO BE WEIGHED. DO NOT GO TO YOUR PIT AND THEN BACK TO THE SCALES. DO NOT STOP AT ANY OTHER PIT AND THEN GO TO THE SCALES. !!!GO DIRECTLY TO THE SCALES!!!
4. Should a car not make weight: