Fair Class cars: any coupe, sedan or station wagon, 105” wheelbase or larger, front or rear wheel drive. No ambulances, hearses, limos, or commercial vehicles. NO IMPERIALS or IMPERIAL SUB-FRAMES.

Mini Cars: any 4 or 6 cyl car 108” wheelbase or smaller, sub-frame cars only – no full frame cars. (No Convertibles)

Fuel Systems

• All vehicles must run on gasoline or diesel. No alcohol.
• Electric fuel pumps are allowed, but must have shut off switch in reach of driver.
• All fuel lines and fittings must be leak proof.
  
• Stock fuel tank MUST be removed. Fuel tanks must be mounted in the rear seat area of vehicle (in front of rear wheels on wagons), or use a fuel cell (metal/plastic marine boat tank may be used). Fuel cells and tanks must contain no more than 6.5 gallons of fuel. The fuel cell must be solidly mounted with bolts/threaded rod, metal strapping, or seat belts (no bungee cords, chains, or rope). DO NOT WELD FUEL TANK TO FLOOR (yes, I’ve see someone try it…) DhR officials’ decision is final.
  
• Rubber fuel lines must be sleeved with a puncture resistant material (plastic or metal) and secured away from sharp edges, doors and hood, and must run inside car. Hi-pressure rubber lines with compression fittings are also allowed.
  
• Any vehicle suffering a fire will be subject to re-inspection. Yes, we know the difference between an exhaust fire and a genuine accidental blaze.
  

Engine, Transmission, Axles

• You may cut a hole in the firewall to accommodate the engine within reason. Holes in fire wall must have a cover to protect driver from fluid spray or fire flash. NO EXCEPTIONS!
  
• You must have an air cleaner over the carburetor at all times during the event.
  
• No starting fluid will be allowed.
  
• There must be 12x12 inch opening cut in hood in case of a fire
  
• If you are swapping engines: on V-block motors, the #1 spark plug must be in line with or in front of the upper ball joint. On inline motors, the #2 spark plug must be in line with or in front of the upper ball joint.
  
• Any exhaust header may be used, and may exit hood, as long as it points away from driver compartment.
  
• Home made transmission cross members, shifters and shifter linkage, and transmission mounts are okay, but must not strengthen the frame.
  
• Welded or spooled rear ends are allowed.
  
• No welded rims
  
• Valve stem protectors are okay
  
• Wheel weights must be removed.
  
  • Any engine can be used in any car. However, on V-block motors, the #1 spark plug must be in line with or in front of the upper ball joint. On inline motors, the #2 spark plug must be in line with or in front of the upper ball joint.

• Stock motor mounts may be welded; transmission and motors may be chained, only secure motor chains to an existing bolt, do not weld or add plates to attach it to the frame. You may chain OR weld your motor mounts to the cross member only (not both). Mounts and chains must not reinforce frame in any way.
  

Interior

• Remove all the carpet and plastic trim, including padding under the carpet and headliner. Removal of anything that can burn (not including seats and seat belts) is highly recommended. Removal of the dashboard is optional.
  
• Padding of driver door and driver’s door safety bar is recommended.
  
• All drivers’ compartments must be clean of any trash, broken glass or anything that could be a projectile.
  
  • Front seats must be reinforced by installing a seat bar behind and up against the front seat. Seat bars must be welded in place, from the left to the right side of the car. This bar is to be used to keep the seat from collapsing and injuring the driver. It must not be used to overly strengthen the vehicle. It is not to be fastened to the frame of a car in the nostalgia & mini truck classes
  •  Electrical  System
      TWO  automotive batteries may be used and must be VERY SECURELY mounted and covered
      in passenger floorboards (plastic milk crates, battery boxes, wood crates work
      well. Metal doesn’t.)
    
    

  Body and Frame

• Weld zone: 6” in front of front door seams to rear axle center line. This area defines where the majority of the welding may be done on a vehicle. Any welding outside of this area is spelled out clearly in these rules. If you are not clear on what is allowed – inside or out of weld zone, call DhR before you do it, or be prepared to cut it out on race day if it doesn’t pass tech.
  
• No turtle-backing/wedging your trunk.
  
• No painting, buffing, oiling, or undercoating of frames. No questions asked, you won’t be teched. You won’t be allowed to run. Period.
  
• No modifying wheel base!
  
• No body seam welding allowed inside or out, unless specified
  
• The only welding allowed is what is stated in these rules. If you want to weld it and it’s not spelled out here, call or email us first!
  
• Buick, Pontiac, and Oldsmobile frames may fill the large hole in the frame behind the radiator support – butt fit only, no overlap. Only one pass weld.
  
• No stuffing, heat treating, foam filling, or otherwise reinforcing your frame. We will scope your frame.
  
• You may cut/notch frames for minimal pre-bending, but may not weld the cut
  

• Frames may be shortened on 80’s Lincoln Towncars and Mercury Grand Marquis to equal Ford Crown Vics.

• Sub-frame cars may connect front and rear sub-frames under floor of car. Sub-frame connectors may not be tied to the cage or enter into the interior of car. Sub-frame connectors may be bolted OR welded in place 5/8” max. on bolts. Sub-frame connectors may not extend farther forward than 6” into the front sub-frame and no farther rearward than 6” into the rear sub-frame, and may not be connected to or reinforce front or rear arches. NO EXCEPTIONS. A 1” inspection hole must be cut in both the front and rear sub frames 3” into where connectors are mounted for inspection. Do not fill subframe connectors.
  
• On any non-leafed 1978 and newer rear wheel drive GM, 1979 and newer front wheel drive GM, 1980 rear drive FORD and/or Mopar, 105” or larger wheel base, you are allowed a 1/4 inch thick by 22 inch long hump plate, contoured to the hump, centered and welded with one pass of 1/4 weld. This plate must be welded to the outside only, match the factory hump and not span the center of the hump. Do not weld any seams on the rear of the car. Don’t fold it over the top or bottom (no wrap arounds) and it may not be welded to any other metal besides the frame. We don’t want you to weld the body down to the frame.
  
• Front frame seams MAY be welded from the firewall to the engine side of the radiator core support (do not weld the core support to the frame!) on the TOP of the frame only, using no additional material. Only one bead of weld allowed. DO NOT PLATE OR FILL YOUR FRAME SEAMS. NO EXCEPTIONS!
  
• Rear frame rails may not be shortened.
  
• You may run a chain or wire (#9 wire or 3/8” chain max) from rear frame rail to rear frame rail behind the rear humps. No strapping of any kind may be used.
  
• Do not shape your frame. Do not sharpen or square the edges of the frame. The frame humps above the rear tires may be beat inward toward center of car from either side a maximum of 8”.
  
• Newer aluminum Ford engine cradles may be replaced with older cradles, in stock location only, with a maximum of 12” of weld. All other components must be bolted in with OEM stock size bolts. No added metal, braces, or gussets.
  
• You may pitch the front frame section of 80’s and newer cars in one of the following ways:
  
  • Cold pitch – no added metal
    
  • Cut only the outside flap of crush box and pull down front end , moving the flap ½”, and re-welding it. Only re-weld the one flap. Don’t re-weld any other part of the crush box. Do not add additional material.
    
  • Pitch the frame at the transmission cross member.
    

Bolts, Rod, or Chain

• Hood: You may use 4 (four) hood bolts 1” o.d. MAXIMUM, and 2 (TWO) PIECES OF 1” MAX o.d. THREADED ROD. Bolts must be sheet metal to sheet metal only. Front two rods may go through the frame and radiator core support. Washers for bolts & threaded rod must not exceed 6” diameter and ¼” thickness, 2 per rod/bolt. The front threaded rods that go through the core support may be sleeved with pipe between the frame and core support. Pipe must be free floating.
  
• You may install up to 12(twelve) 3/8 bolts or self tapping screws per hood cut out. You may not have more than 3 cut outs in your hood (2 for exhaust and one for fire extinguisher access/air cleaner). These bolts must be installed in the immediate perimeter of the cutouts. You may not weld the cut outs. Hole for fire extinguisher must be 10” miniumum.
  

• TAILGATES ON WAGONS, TRUCKS AND SUVs, AND DOORS OF VANS. You may weld 5” on, 5” off 2” x 1/8” strap. Strap must not exceed 5” per section.
  
• If you choose not to weld, you may secure with 4(four) 1” bolts (two 6” x 1/4” washers per bolt) OR you may weld four 5” sections of angle iron to the tailgate and quarter panels and fasten together using one 1” bolt per section of angle iron. Pick one option only.
  
• TRUNKS (use all means of securing trunks listed below): Weld 5” on, 5” off, with a 2” x 1/8” strap max. Strap must not exceed 5” length per section. You may also weld four (4) 5/8” max threaded rods vertically to the sides of the frame, up through the trunk lid. You may use 8 (eight) ½” inch bolts in the drip rail, which must be sheet metal to sheet metal only. Washers for threaded rod must not exceed 6” diameter and ¼” thickness.
  
  • If you choose not to use bolts to secure hood or trunk, you may use 8 lengths of wire or chain on trunk, or 4 on hood, sheet metal to nearest sheet metal – no crisscrossing trunk or hood compartment. Maximum 6” washers on each wire or chain, may be welded in place.
    NO THREADED ROD GOING FROM SIDE TO SIDE of trunk or tailgate
    
    
  • You may not wedge your trunk. Tucked trunks okay. Rear quarter panels must remain vertical. Trunk seams must remain visible. Trunk lids may be “V”ed in the center but must remain a minimum of 12” off the floor of trunk. Speaker deck may only be “V”ed 10 inches – do not pound it low. Keep the speaker deck in stock location.
    

Reinforcements

• No radiator frames. The extent of an allowable type of radiator protector is the type of steel screen that can be folded over the top of the radiator and fastened to the radiator only. It is not to be fastened to the core support or frame. Its purpose is to keep the radiator free from packed mud and deflect rocks, not Buicks. If we can’t twist it by hand, it’s a reinforcement, and not legal
  

• Skid plates are allowed, and must be separate oil/transmission pan plates. No full-length skid plates. No bolting or welding to frame.
  
• Engine protectors are allowed, but must be similar to the BRP product shown below. I can’t tell you who you have to buy your stuff from, but this product represents the absolute MAXIMUM engine protector allowed.
  
  

Make sure yours is built like this or LESS.

• Rusted out floor pans may be repaired where components will be mounted or for driver’s safety, sheet metal only. You may not patch clean solid floors.
  
• Coupes and sedans only, are allowed a gas tank protector, no wider than 24 inches, AND MUST NOT BE ATTATCHED TO ANY SHEET METAL. A ONE INCH SPACE IS MANDATORY. It may NOT run back to frame humps. IT MUST RUN STRAIGHT BACK, BUT ONLY IN THE CENTER OF THE CAR. It may not be any taller than the seat bar, and may only be attached to seat bar and no other part of cage or car.
  
• You may run 1 chain 3/8 MAX. or 4 loops of #9 wire from frame rail to frame rail behind rear axle.
  
• You may smash inner and outer door skins (includes tailgate) together and weld TOP SEAM ONLY. NO ADDED MATERIAL MAY BE USED.
  
• You may add 2 loops of #9 wire, four strands per loop in any window opening. This wire may go to or around the frame. Station wagons may not use wire in any window past 2nd row of seats. Ex: no wire in tailgate window and large rear side windows above the quarter panels.
  
• Distributor protectors are allowed, attached to engine and transmission only, and must not contact cage before, during, or after event. If you run a distributor protector, do not mount your dash bar closer than 5” behind rear most part of cowl/firewall. Distributor protectors may not be welded, bolted or chained to body, hood or frame. Outer dimensions of the distributor protector must not exceed the center of the valve covers on the sides and go no father forward than the water pump. Cutting a hole in the firewall for distributor access is allowed. Distributor protectors are allowed, but must not keep the engine/front end from bending, and must be 1” or more away from the firewall at the start of the derby.
  
• No added weight to the car except for the weld. No buffing, grinding, pinning or packing the frames, trunks, doors, or under floor. ABSOLUTLY NO BODY SEAM WELDING OTHER THAN OUTER DOOR SKINS.
  

BODY MOUNTS

• All body bolts must be max 5/8” O.D or smaller (does not apply to threaded rod through core support and front 2 body mounts). Body bolts MAY extend below frame. Body mounts must remain in factory location.

• Body pucks may be removed and the body may be bolted directly to the frame. Washers (not pucks) for the body mounts must not exceed 6” diameter and ¼” thickness, two per bolt, and must remain free-floating.
  
• You may add 2 additional body mounts. Additional mounts must be painted for easy viewing. If your station wagon came with body mounts in the rear humps, these count as your two additional mounts. If you choose to bolt your coil springs in place through the package tray & frame, these will be you two additional mounts. Wagons may run two of the 4 rear mounts through the rear most pillars (not the roof) – they must be in the pillar at the tailgate area. Chrysler products may drill a hole in the frame right behind the core support and run 1” all thread there. This will count as your two added mounts. Do not weld the all thread in place,
  

Cage

• A pipe or bar behind the seat is mandatory (bar may only be positioned max 18” behind the back of the seat). An optional pipe may also be put in the front where the dashboard was located, in between the front door posts. A 6” by 6” plate at the end of the pipe may be welded to the interior of the car behind the seat and the bars must be welded to these plates. You may connect the bar behind the seat and the dash bar with a bar on both the drivers and passenger side to make a 4 point box style cage. These interior door bars may extend no farther than 18” behind the driver’s seat. Halo bars are allowed. VERTICAL DOWN TUBES MAY BE ADDED, MAXIMUM OF 4, AND MAY BE ATTACHED TO TOP OF FRAME. NO FORM OF KICKER ALLOWED. Down tubes may not be attached to or conceal a body mount. All horizontal cage bars must be a minimum of 8” above floor (INCLUDING GAS TANK PROTECTOR)
  
• Halo bars must be vertical and not at an angle. They must not attach to the rear deck. Halo bars may not exceed 6” outer diameter. Halo bars must attach to the cross bar that is no farther back than 18” behind the driver’s seat.
  
• No kickers from halo bar to the rear deck or trunk.
  
• No rear window bars allowed
  

Bumpers

• Bumpers must be mounted in stock location (on frame).
  
• All bumper brackets and shocks must be OEM automotive grade material.
  
• No bumper chrome may be welded to the body
  
• Front bumper brackets/shocks may be welded no more than 4” behind the core support and rear brackets may not be welded no more than 4” onto frame rails.
  

• Bumpers may be welded directly onto frame. Do not add additional material to assembly. Weld stock pieces to stock pieces only..
  

• You may weld a 2” by 6” long x ¼ FLAT strap from bumper to frame. This must be a one piece strap and must not run at an angle in any way. Welding it to the flat top part of the bumper and frame is recommended. One pass of weld only.
  
• Bumpers may also be wired to core support using 4 loops of #9 wire in two locations, outboard of radiator.
  

• Bumpers must be stock factory style bumpers. Any automotive grade bumper may be used on any car (Super Trucks and MINIs included). No truck bumpers or wooden bumpers on cars.
  
• You may weld bumper chrome to backing, using no additional material other than the weld itself. Bumper ends must be open. Officials must be able to clearly see inside.
  
• You may replace your front bumper with an aftermarket DEC bumper. YOU MAY REPLACE THE REAR BUMPER WITH A STEEL SQUARE TUBE 4” DIAMETER, ¼” MAX THICKNESS.
  
• Front bumpers must be stock or D.E.C. replacement. However, due to the rising costs of bumpers, you are allowed to re-enforce the bumper on the inside or backside between the shock mounts. This re-enforcementmust be no larger than 6inch wide by 1/2 inch thick and may not be mounted no wider than 1/4inch past the outer wall of the frame. Do not re-enforce the front of the bumper or the ends outside the shock mounting area. Bumper re-enforcement may not be done in anyway to stop frame bending. Bumper must appear stock. Bumpers used on the rear of vehicle may not have any reinforcements of any kind. If you choose to run a front bumper on the rear of your car, you may not reinforce it.
  
• On Chrysler pointy bumpers (70s New Yorker/ Imperial) or any bumper that does not have a flat backing you may plate the space between the front bumper and the horizontal reinforcement using maximum 1/4“ thick plate. If your bumper doesn’t have a horizontal reinforcement (Monte, Cutlass, etc…) you may plate horizontally back to the fartherst rearward part of the bumper. Do not weld the plate to anything other than the bumper and the horizontal reinforcement

  Body Panels

• If you do not weld your doors you must chain or use #9 wire, at least twice per seam. You may not bolt or seat belt your doors shut. If chaining or wiring, none may go thru or around the frame.
  

• Fenders, quarter panels, wheel wells, and bumper ends may be trimmed for wheel clearance. Fenders, quarter panels, and wheel wells may be screwed or bolted back together if trimmed, using a maximum of 5 screws. Screws/bolts must not exceed 3/8” outer diameter, and must not protrude away from body more than 1/4”.
  
• The body CANNOT be welded to the frame.
  
• No doubling of body panels.
  
• No welding core supports.
  

FRAME REPAIRS
Note: DAMAGE MUST BE OBVIOUS OR REPAIR WILL BE DEEMED EXCESSIVE.

• Do not repair rusted out frames. Pick a better car.
  

• You may fix a broken factory frame seam weld by making ONE PASS OF WELD OVER THE DAMAGED AREA ONLY. NO ADDITIONAL MATERIAL MAY BE ADDED. Broken frame seam welds may be re-welded no stronger than stock, using no additional material.
  
• You may use up to 4 4x6 3/16” thick plates to repair kinked frames (not including rear arch plates on applicable cars). Only 4 may be used over the total life of the car. If you plan on using the plates, e-mail or text me a photo that includes a close up of EACH article of damage and a shot of the car from far enough away that it will be recognizable on race day, and a description of the requested repair(s). Plates may overlap the damaged area by a ¼ inch. DO NOT do any repairs until you receive authorization from me via e-mail or text. Such communication will be on file on race day. Verbal communication does not count. You may not add the 4 plates to a fresh car. DhR officials’ decision is final.
  

• You may re-stub front frame sections. The only acceptable way to do this is to cut off the frame under the driver’s seat, before transmission cross member and behind crush box/front frame arch, and weld on a new frame section. You may weld the cut and then weld a strap 1/8” thick, 1” wide over the cut, having a ¼” overlap on either side of the cut. No additional reinforcements of the frame allowed.
  

SUSPENSION & STEERING:

• Leaf springs must be of stock-type material and must taper largest to smallest (each leaf 4” smaller than the next largest – 2” per side), with only one main leaf. Leaf springs must be made of spring material, no sheet metal or flat stock. No welding of leafs. Max 9 leafs per side. No flat stacking your leafs. No leafs on top of main leaf.
  

• Leaf spring clamps may be replaced if defective. Home made spring clamps are allowed, but must not exceed 3 clamps in front of and 3 clamps behind axle per side. Home made spring clamps must not use material thicker than 1/8”, no wider than 1”, and use bolts no wider than 3/8” o.d.
  
• Do not double stack leafs. Do not invert leaf springs. Leaf springs must be mounted in OEM stock position, no moving shackles.
  
• ALL VEHICLES MUST HAVE WORKING BRAKES!
  

• Stiff or locked suspension is allowed, but must not reinforce the frame in any way. Locking the A-arms may be done with chains, bolts or welds and must be done in the center of the front control arm
  
• You may tilt rear end by shortening or lengthening STOCK rear control arms. No excessive reinforcement. Rear upper and lower control arms may be boxed (not solid).
  

• Suspension & steering must start out as O.E.M. (original equipment), and automotive grade. Boxed control arms, A arms and reinforced tie rods okay.
  
• Coil spring cars may not be changed to leaf spring cars.
  
• No putting leaf springs on top of the axle.
  
• No welding of leaf springs.
  
• Do not duct tape leafs. Period.
  
• Rear end braces allowed, but may serve no purpose than to strengthen the rear axle housing. They may not extend more than 6” from rear end and may not be higher than the top of the rear axle housing.
  
• You may reinforce tie rods. You may make your own pipe sleeves. All tie rods must use OEM factory equivalent tie rod ends.
  
• Ford watts link conversions are allowed. You may convert your watts to a standard 4 link system in the following way: Use the upper and lower trailing arm brackets off an older Ford. Aftermarket brackets are allowed, but must not be thicker than ¼ “ and may be attached with a maximum of three ½” bolts on each side. If you are converting to a 4 link, do not shorten trailing arms. Do not position brackets to strengthen front arches of rear hump. Brackets must be in stock location. All mounts must be in stock location.
  

TIRES AND WHEELS:

• Any tire may be used, but must not exceed 16.5” wheel diameter.
  
• Welded rims okay, however must meet approval of DhR officials.
  
• Valve stem protectors are okay.
  
• Solid, water filled, tubed tires, and doubled tires are allowed
  
• Wheel weights must be removed.
  
• All cars must demonstrate the ability to stop. If your brakes don’t work, you don’t compete.
  

TRANSMISSIONS & COOLERS

• Transmission coolers will be allowed BUT MUST HAVE A SPLASH SHIELD TO PROTECT DRIVER.
  
• Metal or steel braided line must be used. Rubber lines must be double clamped and SLEEVED WITH HEATER HOSE OR SIMILAR MATERIAL. No fuel or low pressure lines may be used.
  
• Any transmission cooler that has been relocated to the inside of the car must be enclosed or covered.
  
• Overall safety/legality will be determined by officials at time of inspection.
  

COOLING SYSTEM

• Radibarrels may be used instead of a radiator. Radibarrels must hold no more than 8.5 gallons, have a pressure release valve to blow off steam, be no more than 4" thick, 31" long x 16-1/2 tall or smaller, be constructed of 1/8” thick steel or aluminum only. have two mounting brackets with no more than 3 mounting bolt holes in each, and a radiator cap. This is a DERBYPROFAB example:
  

• Radibarrels must be bolted, strapped or wired to core support, and may not be attatched to the frame in any way. Radibarrels may not reinforce the car in any way.
  
• Engine and radiator/radibarrel must be flushed free of anti-freeze. Water only! Please flush coolant before arriving to the track.
  
• Electric fans are allowed.
  
• Any automotive radiator may be used, but must be mounted in stock position. NO HOME-MADE RADIATORS! Note: radibarrels allowed in Fair Class (not auto soccer cars, minis or Nostalgia Truck) and Super Truck Class only.
  
• If you choose to compete without a radiator, the mechanical fan must be removed. No reserve tanks are allowed. Driver must compete with the water that is in the engine block only, or run dry block.
  
• Heater cores may remain in stock position, but removal is strongly recommended. No excessive radiator or heater hose lengths for additional coolant allowed
  
• No radiator frames.