Big Car Rules | Demolition Derby Big Car Class Rules 2026

LFR Promotions Big Car Bash

Build Rules and Regulations

If you have any questions about the rules, don't just guess! Call or text Conner at 541-589-0517.

Open to any full size car, station wagon and 1967-73 stock Imperials. NO hearses, ambulances, commercial vehicles, or pre 1967 Imperials. See Imperial rules.

PLEASE NOTE: ALL COMPETITORS FOR THE DESCHUTES COUNTY FAIR (DCF) DEMOLITION DERBY MUST BE 18+

Section 1: General Arena/Pit Rules

● Absolutely no alcohol or intoxicating substance for drivers during the event.

○ Any Driver or Pit Member, signed in under the car, found to be under the influence of drugs or alcohol, will disqualify the car for the remainder of the event.

● All drivers must present a valid driver's license or learner's permit and sign a release of liability waiver. .

○ Participants 15-18 years of age must have a parent or guardian sign the entry form and release of liability waiver. REMEMBER: 18+ for DCF

● No one under the age of 15 will be allowed in the pit area after 12:00 PM until the event is over. 18+ for DCF

● Cars must be towed or trailered to the event and must be removed from the grounds after the event.

● Upon Registration there will be a $0 fee.

○ This covers the entry for the car, driver and one pit member. Additional pit passes are $20.00 each. Pit members must sign a release of liability waiver.

● There will be 2 car heats, a powderpuff and the main event.

○ All cars that participate in a heat or the powderpuff are eligible to return for the main event.

○ The car qualifies, not the driver, i.e. a puff car can be driven in the main by a male driver as long as he has signed the waiver and entry form and must be declared upon registration.

○ Women can drive in the main event if they choose to do so.

● Heat assignments will be determined at the time of the event by order of inspection and will be run in the following order; Powder Puff, Heat 1, Heat 2, Other Classes, followed by the Main event. (subject to change)

● No one is allowed in the arena area during the event.

○ Only officials will be allowed to be on the arena side of the fence during the events. If you fail to stay on the pit side of the fence, you will be asked to leave.

○ At the conclusion of all heats/classes, there will be a 45 minute intermission to prepare for the Main Event.

● Drivers must stay in the car until the heat is over or the event has been stopped by officials.

○ Any body part outside of the car other than an arm will immediately disqualify the driver, and they will forfeit any prize they may have won.

● Only one person will be in the car when participating in the event.

● Drivers must have an approved full face helmet. NO bicycle, football or half helmets allowed.

● Drivers will stop at the gate before entering the arena so officials can check and make sure helmets are secured and seat belts are on. If a driver is found to not be wearing a seat belt or not have their helmet properly secured, they will not be allowed to enter the arena until they put their seat belt on and secure their helmet properly.

● A seat belt must be worn AT ALL TIMES. (see seatbelt section)

○ If you fail to wear your seatbelt for the entirety of the heat or main event, you will be disqualified and forfeit any prize you may have won.

● Drivers may do a “HANDS-OFF” inspection of other cars.

● No intentional hitting of the driver’s door. The judge’s decision is final.

● In the event of a roll over, the event will be stopped until the vehicle is upright. ○ Roll-over cars will not be allowed to continue.

○ If the vehicle is flipped on its side, it will be the judge’s discretion if the vehicle is safe to continue.

○ If a car is disqualified in any heat for any reason, it is allowed to advance to the main event if the officials deem it safe to do so.

● All drivers will stop in case of fire, roll-over, or other emergencies. ○ Drivers must remain in the car unless declaring themselves out of the competition.

○ It is the driver’s decision to shut off the motor under these circumstances, unless directed otherwise by an official.

● No radio or cell phone communication allowed in the arena.

● Flags will be up during the heat and the main event until drivers take themselves out of the competition.

○ If you break your flag, you cannot reenter the action. If you break your stick or wave your flag in a heat, you are automatically out and forfeit your placement if there are still other cars on a timer. i.e. if there are three competitors remaining in action and you break your stick you will default to third place. If there are four you default to fourth, and so on

○ You will be given 2 flags upon passing inspection.

● All cars must be in continual action.

○ Cars cannot be out of action for 2 minutes or you will be told to pull your flag. Cars must make a hit every 2 minutes or be disqualified, meaning unassisted contact in forward or reverse under their own power. Rocking back and forth is not considered a hit. NO SANDBAGGING!

● Any car or driver the officials deem to be unsafe or a hazard will be ordered to stop and take themselves out of competition.

○ A car will not be allowed to compete if the judges find it to be unsafe prior to a heat or the main event.

● Most aggressive Driver will be determined by all officials and event staff! ● Judges decisions are final

● This really shouldn't have to be here, but drivers must stay seated in their seat for the entirety of the heat. Absolutely no standing up to fix something while you are competing. If a driver fails to stay seated, they will immediately be disqualified.

● All drivers must refrain from intentionally pushing cars through logs/barriers. This creates a safety hazard for officials and emergency crews around the track. ○ If you intentionally push a car through/onto the logs/barriers, you will be told to break your stick for intentionally breaking rules.

○ If you are pushed onto a log/barrier and can not get yourself off, we will pull you off.

○ We understand accidents happen, but intention to push someone through the log/barrier is clear. Help us keep this event as safe as possible for officials and emergency crews so we can continue to have it.

Section 2: Car Preparation

Build to the rules, do not overbuild. If your car is found to be altered in any way except for what is specified below, you will be asked to cut or load up and go home. If you try to argue with tech officials and be belligerent, you will receive a 1 year ban for the first offense. Meaning you will not be allowed to compete in the next year's event. In the event of a second offense, you will receive a lifetime ban. You may still attend the show as a spectator, but you will not be allowed to compete.

● (a) All glass must be removed.

● (b) Flammable materials inside the car must be removed.

○ Trunks must be free from any debris.

○ The inside of the doors must be clear of all glass and debris.

○ All light covers/bulbs, side mirrors, hubcaps, grills, side chrome, plastic, door handles and pot metal must be removed.

● (c) All trailer hitches, related brackets, reinforcements and hardware will be completely removed.

● (d) You must have a number sign securely mounted to the roof and numbers must be clearly visible and contrasting colors to the car. Numbers must be a minimum of 18 inches in height.

● (e) Cars must have a minimum of two working hydraulic brakes.

● (f) You must have either an air cleaner or suitable flame arrestor. A large hole must be cut in the hood, at least 12" in diameter, and must be put in the hood for fire extinguisher access. Header holes are acceptable for fire access holes if they are large enough. The judge's decision is final.

○ No alternative starting methods i.e. starting fluid etc…

● (g) Any tire may be used. Doubled and forklifts are ok. Valve stem protection is permitted. Valve stem protection may only be made of ⅜” round stock or ⅜” rebar. No beadlocks/bead protection allowed.

● (h) Transmission coolers other than stock, if used, must be relocated inside the vehicle. (Recommend covering lines and double clamping all connections)

● (i) Exhaust pipe must be cut in front of the rear axle. You may use upright headers.

(j) Any rear end may be used as long as it is OEM to A car. No ¾ ton truck rear ends.

Section 3: Fuel Systems

● (a) Stock fuel tanks must be removed or have a 6 inch hole knocked in it at the lowest point.

● (b) Gas tanks must be a safe container and made of steel. Example: boat tank, saddle tank or fabricated tanks, and must be approved by an official. ○ NO PLASTIC tanks or jerry cans.

○ Gas tanks must be bolted and/or chained solid to the car body and must

not connect to the frame.

○ Tanks must be capped with a leak proof cap and placed directly & securely behind the driver area or in the center of the rear seat area. ○ Tank must be mounted inside of the frame rails of the car.

○ If a vent tube is used it must extend out of the passenger compartment.

● (c) Gas lines and fittings must be leak proof. (NO EXCEPTIONS!! Double clamped is strongly recommended)

Electric fuel pumps are optional. If an electric fuel pump is used, you must have an on/off switch that is positioned so that up is on and down is off. The switch must be easily visible and "off" must be clearly marked.

Section 4: Batteries

● (a) Batteries must be removed from the engine area and relocated inside of the vehicle and placed in a securely mounted approved battery box, placed in the passenger floor area.

○ Battery box must be of metal construction, and securely fastened to the floor.

○ In NO way may it be connected/bolted to the frame.

○ All batteries must be covered with rubber (inner tube) to protect the driver. ○ No wooden boxes or plastic milk crates.

● (b) Two (2) batteries maximum

● (c) Switches or wires used for powering off the car must be within reach of the driver while harnessed in.

Switches need to be clearly marked on/off and orientated where up is on and down is off.

Section 5: Safety Bracing

allowed to compete in the next year's event. In the event of a second offense, you will receive a lifetime ban. You may still attend the show as a spectator, but you will not be allowed to compete.

● Cages may be gusseted.

○ Gussets must be made of the same material your cage is made of. ■ Gussets may only be 12” at the longest point.

○ Uprights may also be gusseted

○ Maximum of six (6) gussets allowed. One at each corner of the cage, and one on each upright.

○ Gussets on down bars will NOT be permitted.

● (a) A front cross brace may be installed above the steering column from window post to window post if the dashboard is removed (in the former position of the dashboard).

○ It must be made of a minimum 2" pipe or square tubing with minimum of 1/8" wall thickness and be securely fastened into position.

○ The dash bar in no way may touch or be bolted to the frame of the vehicle. ○ If a 2 piece brace is used, it must be securely fastened so that it cannot collapse. (Welded or minimum 3/4" bolt)

● (b) A rear cross brace must be installed from door inner skin to door inner skin, as close to the door post (B pillar) as possible, and at least halfway up from the floor.

○ It must be made of a minimum 2" pipe or square tubing, with plates welded on the ends.

○ The end plates may not extend more than 12" past the cross bar (towards the rear of the car).

○ The cross brace must be securely attached! Either bolted to door skins with a minimum of two ¾" bolts per side, or welded to the B pillar, or both.

○ If the cross brace is collapsible, it must be pinned with a ¾" bolt (minimum) or welded so it can’t rotate or collapse.

● (c) Both front doors may be reinforced with a minimum 6" wide, 3/16" thick channel iron, or a Grader blade.

○ The side iron must not be more than 6’ in length and must begin ahead of the front door seam and be no more than 6" in front of the front door seam.

○ Door bars may not extend over the edge of the wheel well openings.

○ The iron must be bolted with a minimum of three (3) bolts (3/4" min) that extend through the inner panels.

○ Backing plates (washers) must be used and must be a minimum of 4" x 4" x 3/16" thick on both front and rear ends of the door bars.

○ The front bolt must be located through the A pillar/electrical knockout, at least one other bolt must go through the plate connected to the rear cross bar.

○ The ends of the side irons must be cut at a 45-degree angle.

○ If your door bar comes off during the derby you will be disqualified.

● (d) Inside cages/door bars will be held to the same standards as the above. With the exception that the cross bars can be welded to the door bars to create a 4 point cage.

○ It must be securely fastened by bolting through the door with a minimum of three (3) bolts (3/4" min) that extend through the inner panels.

○ Backing plates (washers) must be used and must be a minimum of 4" x 4" x 3/16" thick on both front and rear ends of the door bars, and or welding the door bars to the door skins and A and B pillars. If welding to the pillars and door skins, a minimum of 4 (four), 2 inch weld per side.

● (e) Uprights/halo bars are mandatory, NO EXCEPTIONS.

○ They must be behind the seat and securely fasten to the TOP of the rear seat bar.

○ The upright on the drivers side may go to the floor and be securely mounted with a maximum 8” x 8” x ⅛” plate TO SHEET METAL ONLY.

○ The top crossbar across the roof must be welded to the roof with 12” of total weld on BOTH sides of the bar. It may be stitch welded or a solid weld not exceeding 12” along the center of the bar or can be bolted to the roof with a minimum ⅜” bolt in 6 places.

○ Uprights on the drivers side must be padded at head level.

● Gas tank protectors may be used but they can only be attached to the rear cross bar. ○ GTP’s must be centered between the frame rails

○ Must not exceed 34” in width, or 4” above the gas tank

○ GTP’s must be a MINIMUM of 2” away from any sheet metal and rear window bars. ■ Sheet metal can not be removed or altered to achieve this.

○ You may use one 12” gusset, per side, that goes from the seat bar to the protector.

● Down bars are permitted ○ You may have a MAXIMUM of four (4) down bars on your cage, one at each corner.

○ Down bars may go through the floor of the car and connect to the frame

○ Down bars must be a minimum of 2” pipe or 2”x2” square tube and a maximum of 3” pipe or square tube and must be securely fastened to the cage.

Section 6: Seat and Seat Belts

● (a) Approved safety harnesses or functioning OEM belts are mandatory. ○ No ratchet straps, wire, or rope!!!

○ They must be mounted to stock mounts or have a 2" minimum flat washer where it is mounted through the sheet metal.

○ Lap belts are acceptable!

(b) Seat can be OEM stock of any make/model car. A headrest is recommended. ● (c) No fiberglass/plastic racing style seats.

Section 7: Building, Welding & Securing

THERE WILL BE NO OTHER WELDING OTHER THAN WHAT IS STATED BELOW. IF YOU HAVE A QUESTION ABOUT WELDING, PLEASE CALL THE HEAD TECH OFFICIAL!! IF WELDING IS FOUND ON THE FRAME OR SHEET METAL THAT IS NOT SPECIFIED BELOW, YOU WILL BE ASKED TO CUT OR LEAVE!

● (a) You May weld the frame seams from the A-arms forward.

○ ½ inch wide welds max!!!

○ Absolutely no added metal.

● (b) You may fully weld all FACTORY body seams.

○ You may use filler no larger than 2"w X 1/8" thick or 3/8" re-bar or equivalent no more than.

○ If chaining the doors shut, you may use chain no larger than 1/2". ○ You

may wrap chain from roof to upper window well, as well as two wraps per door on the lower door to floor of car. (These may go around frame, highly recommended on passenger door)

● (c) Trunk lids, tailgates and hoods must be secured shut with bolts, chains or welds as follows:

○ (i) Hoods can be bolted in a maximum of 6 places other than stock, if not welding hood to fenders, in which only 2 may go to the frame. (Drilled or welded to side or top of frame)

■ Bolt size must be a minimum of 5/8" and a maximum of 1". MAX plate size is 6" x 6".

■ Bolts must not exceed 4" above the vehicle surface.

■ HOODS MUST BE OPENED FOR TECH!! (or have a large enough hole for full inspection)

○ (ii) Chains must be a minimum 1/4" & maximum of 1/2" welded type. A bolt no smaller than 5/16" & maximum of 1/2", with washers, must connect the chains.

○ (iii) Trunks may be fully welded shut along the top of the trunk (seam closest to the rear window) and the seams along either quarter panel; you may use filler no larger than 2"w X 1/8" thick or 3/8" rebar or equivalent.

■ You may add 4 bolts, of which only 2 may go to the frame or

through the floor pan of the trunk.

■ If bolting, plate size cannot exceed 6''x6''. All thread (1" max) may go through frame or be welded to the side of the frame.

■ Cars must have an inspection hole in the trunk. (Speaker deck will count as inspection holes if speakers are removed)

● (d) Bumper swaps are allowed, however you must use factory hardware (brackets/shocks) {one shock or one bracket per corner not a combination of both} these pieces must be OEM original to any make of car.

○ Bumpers and hardware can be from any make of car, or open pipe/square tubing with a minimum of 2” x 3” and a maximum of 5” x 5”.

■ There must be a clear view through the pipe/square tubing, Square tube bumpers must have a plate welded on either end with a minimum 1” hole for insection. Square tube bumpers MAY NOT have an added point. NO homemade bracketry and NO homemade bumpers, the only exception being the pipe/square tubing! Any questions....call tech.

● (e) Front and rear bumpers may be welded solid. (I.e.-bumper to bumper shock, shock to bracket and bracket to frame)

○ No extra metal.

○ Bumper shock itself may be collapsed and welded.

○ No added material.

● (f) Bumpers (front and rear) may be welded directly to the frame. ○ No added metal other than filler material.

● (g) You may weld the outer skin to the inner structure of the bumper.

● (h) You may weld in engine straps, Maximum of 2 x 2” x1/4” flat plate; straps (like cradles) may not be welded to the frame rails.

● (i) Bumper straps are allowed. ○ For each bumper, you are allowed two 2” wide x ¼” thick x 14” long straps.

○ Straps must be welded to the bumper and body with at least 3” of connection to either side. (3” on bumper, 3” on body.)

● (j) Maximum bumper height is 24” ○ This will be measured from the bottom of the bumper to the ground.

Section 8: Radiator and Radiator mounting

● (a) An electric cooling fan is permitted. Fan must be ran to an on/off toggle switch which is clearly marked and oriented where up is ON and down is OFF

● (b) The original core support must be OEM to that make, model and year of car, and fastened in with the factory bolts and bolt holes. Absolutely NO welding in the core support.

● (c) Radiators MUST be mounted in the stock position using factory bolts and bolt holes, seat belts, or ratchet straps. Absolutely NO welded mounting of the radiator is permitted.

● (e) Absolutely no additional coolant/water capacity allowed

● (f) Absolutely no use of spray foam as filler will be permitted

(g) Looped lines are permitted

Section 9: Plates and Pre Ran Cars.

Use your best judgment, if you think it’s too much it probably is. Frame repairs:

● Fresh cars will be allowed two 4”x6”x1/4” plates, one on either frame rail. Fresh cars will not be allowed any more plates than one per frame rail.

● You may repair damaged frame with no more than 1/4” thick plate not to exceed 2” on either end of the damaged area.

○ You may not plate top or bottom of the frame, only the inner and outer frame. You will be allowed three 6”x4”x1/4” plates per frame rail. (The 2 allotted plates on fresh cars do count towards this. So if you already have one plate on either rail, you are only allowed to add two plates per rail.)

○ Photos will help your case here.

Inspector has the final call and you may be asked to cut it if it’s deemed excessive.

Section 10: Misc. Can & Can't Do

● (a) You may cut the firewall for distributor clearance.

○ You must cover the hole to block fire from getting in the passenger compartment.

● (b) You may clamp leaf springs, 5 clamps per leaf. 2"x1/4" MAX, two 3/8" bolts per clamp

● (c) Body mounts may be removed.

○ If replacing bolts, you may use bolts/all thread no larger than 3/4", MAX 4"x4"x1/4" washer/plate.

○ Must be able to see inside the frame.

● (d) You may re-bolt hood skins. 16 bolts maximum. 3/8''max bolt size. 1" max washer size.

● (e) You are allowed 8 3/8" bolts with 1" diameter washers per corner of the car. Not in the trunk or hood.

● (f) Fire extinguishers are NOT mandatory, although highly recommended. ○ If a fire extinguisher is installed in the vehicle, it must be securely mounted and within drivers reach.

○ We suggest having one in your pit area.

● (g) You may chain the humps.

○ You will be allowed 1 wrap of chain.

○ It may go around the rear end 1 time and up through the body and around the frame 1 time and be bolted together.

○ If you don’t chain your humps you may run chain from rear rail to rear rail behind the rear humps.

○ 3/8” chain max.

● (h) You may add ¾” bolts in place of drain holes in trunk and passenger compartment, washers must not exceed 4”x4”x ¼” thick.

● (i) Lower engine cradles may be used; they cannot be welded to the frame rails of the car.

○ No halo type protector’s, distributor protectors, pulley protectors, full engine cradles or transmission braces.

● (j) Window bars shall not exceed 2”x2”x 3/16” angle and must be installed down the center of the windshield from top to bottom.

○ You may install them in a manner of which the bottom is wider than the top to form an upside down V or 2 vertical.

○ Window bars must be welded or bolted with a minimum of 3/8'' and maximum of 1" bolts.

○ No sheet metal screws allowed fastening window bars.

○ Rear window bars may be added no more than 6" extension on roof and in no way contact the deck lid, trunk bolts, trunk plates or frame.

○ They shall not exceed 2”x2”x 3/16” angle.

○ Max 2 each parallel with the roof.

○ Window bar(s) can be welded or bolted with a minimum 3/8” and a maximum of 1" bolts.

○ No sheet metal screws may be used to fasten window bars.

● Tie rods/front suspension components must be factory to that year/make/model of frame. ○ Front A-Arms may be welded down using two 2”x6”x1/4” strap, or 3”x3” plate.

● Transmission crossmember must be bolted with at least 2 bolts on either side of the transmission with a minimum of ⅜” bolt and a maximum of ¾” bolt. ○ You may weld the crossmember in place of bolts. YOU MAY NOT DO BOTH. If welding, you are allowed a maximum of 8” of weld preside of the transmission (4” on the front side, 4” on the backside.)

Section 11: Stock 1967-73 Imperials

Sections 1-6 apply to Imperials as well. If it is not stated here, then you cannot do it.

● (a) Welding of the driver’s door and safety cage (See section 5. Only exception is downbars may only go to the floor of the car. DOWNBARS MAY NOT CONNECT TO THE FRAME ON IMPERIALS)

● (b) All other doors may be secured shut by stitch welding 4” on and 6”off with ⅜” rebar, 2”x1/8” strap or equivalent. Hood and trunk may be secured as follows:

○ (i) In the hood you may run two bolts at the core support that are drilled through the frame no larger than 1” in diameter. And two at the back of the hood to keep it from coming in the driver’s compartment; these must NOT go to the frame, sheet metal only.

○ Absolutely NO welding the bolts to the frame in ANY manner.

○ (ii) Trunks may be secured in the same way as doors, stitch welding 4” on and 6” off.

● (c) You may cut the firewall for distributor clearance.

○ You must cover the hole to block fire from getting in the passenger compartment.

● (d) You may clamp leaf springs, 3 clamps per leaf.

○ 2"x 1/4" MAX, two maximum 1/2" bolts per clamp

● (e) You may use any motor and transmission combo.

● (f) Only the stock bumper from that year/make/model will be allowed to run on imperials.

○ Bumpers must be BOLTED on using the factory bolt holes.

○ Bolts may not exceed ½” in diameter if not using the factory bolts.

○ DRILLING OUT BOLT HOLES TO MAKE LARGER BOLTS FIT IS PERMITTED!

For any questions or clarifications on the rules, contact Conner at

(541) 589-0517