Mini Modified Rules

Mini Modified



The rules and/or regulations set forth herein are designed to provide for the orderly conduct of racing events and to establish minimum acceptable requirements for such events. These rules shall govern the condition of all events, and by participating in these events, all participants are deemed to have complied with these rules. NO EXPRESSED OR IMPLIED WARRANTY OF SAFETY SHALL RESULT FROM PUBLICATIONS OF OR COMPLIANCE WITH THESE RULES AND OR REGULATIONS. They are intended as a guide for the conduct of the sport and are in no way a guarantee against injury or death to a participant, spectator or official.

The race director shall be empowered to permit reasonable and appropriate deviation from any of the specifications herein or impose any further restrictions that in his/her opinion do not alter the minimum acceptable requirements. NO EXPRESSED OR IMPLIED WARRANTY OF SAFETY SHALL RESULT FROM SUCH ALTERATION OF SPECIFICATIONS. Any interpretation or deviation of these rules is left to discretion of the officials. Their decision is final.

The Management of Huntsville Speedway

Warning!  If you attempt to abuse the minimal amount of rules set forth by Huntsville Speedway for the 2023 Mini Modified Division, we will have no choice but to refuse your request for participating.  Just because the rules don’t say you can’t, does not mean that you can!


Refer to Huntsville Speedway’s General Rules for a full list of rules regarding driver, pit and car safety.

Technical Rules

1. The word stock as referred to in the following rules mean “As it comes from the factory in non hi-performance mass produced automobiles”.

2. Top 3 finishers after the race will go immediately to tech.  Fourth and Fifth place go to holding area until top three have been released from inspection.

3.  All starts will be double file, cone rule will apply on restarts.

4.  The 1st place finisher from the previous event will start in the rear of the next race he or she competes in regardless of the draw or qualifying order.

5.  Racing radios and neck restraints recommended.

6.  All competing cars must supply HS with a spark plug that fits your car for tech purposes.

7.  Management reserves the right to alter, change or adjust weight limits to all conforming and non-conforming cars without first consulting with competing drivers.


1. Huntsville Speedway American Racer Tires labeled Mini Modified American Racer tires or the AR-782 tires only.

2.  8″ wide steel wheels only. 

3.  No wheel adapters.

4.  Must have 1” lug nuts.

5.  No wheel weights.

6.  No beadlocks, air bleeders or pop-offs.

Roll cage

1. Bars must be at least .095 gauge 1 1/2” OD steel pipe.

2. Bars must be welded to frame and have 4 protective bars on driver’s side and 3 protective bars on passenger side. No square tubing.

3.  Steel plating required inside of driver side of roll cage at the door and a minimum of 1/8” thick.

4. All cages must meet approval of HS Officials.

Engine Location

1. Stock location (engine face must line up or must be in line with center of upper ball joints). If engine is setback further than the rule states you must relocate 50 lbs. of cars total weight in front of the front spindles. This is not an extra 50 pounds.  Maximum setback allowance 3″ from center of upper ball joints. Weight must be centered or right of center. Engine must be centered in frame, +/- 1″.


1. One 12-volt battery only.

2. Electronic ignition permitted. MSD type boxes permitted.

3. No electronic or mechanical traction control of any kind permitted.

4. No coil packs or crank trigger ignitions.

5. Must have emergency cut-off switch within drivers reach and highly visible to safety crew.


1. Only a Holley 350cfm 2bl. carburetor #7448 is allowed. Carb must be visually unaltered except for air horn removal and must fit all HS gauges.  All air entering engine must pass through carburetor venturi.  Unaltered boosters in stock location. Butterfly screws are optional, Stock shaft and butterflies. Choke rod hole may be plugged and choke mount holes sealed with epoxy or comparable material.

2. Maximum 2″ space between carburetor and intake manifold. Maximum includes spacer plate, adapter plate and gaskets.

3. Cold air boxes permitted.

4. No Fuel injected systems.

Cylinder Head

1. Stock production head only. No aftermarket of any kind. No porting, polishing or grinding of any kind. Damaged heads may be resurfaced. Cylinder head boss may be cut down for shorter 2300 adjusters. May have 3-angle valve job. No more than 75 degrees. Valve spring pocket may be cut .0100 deep or may run long valves; stock head/valve diameter, stainless steel valves allowed. Cars running a Ford 2.0 liter head with 2.3 liter valves, but must carry the specified weight for the 2.3 engine.  Ford 2.0 liter and 2.3 liter heads are allowed a minimum of 45cc combustion chamber.   

2. No aluminum heads except stock Toyota.

3. No more than 2 valves per cylinder, unless approved by HS officials.

4. Any size cam. May run adjustable cam gear.

5.  Roller cams permitted with an additional 25 lbs weight penalty mounted forward of flywheel.


1. Any 3 ring flat top piston. Toyota may run dome pistons.


1. Stock crankshaft for engine being used, may be balanced. No grinding, polishing or lightening of any kind.

2.  Minimum crankshaft weight:

Ford 2300cc 30.5 lbs (both large and small journal)

Ford 2000cc  27.5 lbs

Toyota – See HS Official

NO STROKERS, Minimum Engine deck heights is zero (0.000), piston may not extend above block at TDC. (except Toyota)


1. Any steel rod permitted.  No aluminum, no titanium.  


1.  Stock or aftermarket intake allowed.  On stock intake, port matching the head side of intake is permitted.


1. OEM chassis with steel body (this can be tubed from center of rear axle back, with no left side penalty):

Must meet total weight requirements, no left side weight restrictions

Up to 2.0 1900 lbs.

Over 2.0 2000 lbs.

2. Stock Front Clip and/or Stock Chassis with aftermarket body:

Up to 2.0 2050 lbs. 56% Left Side

Over 2.0 2150 lbs. 56% Left Side

3. All Full Tube Frame car or fabricated tubed front clips

Up to 2.0 2200 lbs. 56% Left Side

Over 2.0 2300 lbs. 56% Left Side

4. Steel body Toyota’s w/OEM chassis Up to 1.8L – 2000 lbs., over 1.8L – 2050 lbs with No Left Side rule. Add 150 lbs for aftermarket body, maximum 56% Left Side. Add 150 lbs for full tube frame or fabricated tube front clip, maximum 56% left side.  Speedway reserves the right to amend this rule as necessary.

5. Weight determined by original engine size. Boring .050 over included in weight.

I.E. 2.0 bored .050 over is still classified as a 2.0.

6. All ballast must be attached with two ½” bolts and be white with car number on it.

7. No car over 2500 lbs. will be allowed to compete in the event for safety reasons.

8. 2.5 STOCK truck engine permitted min. weight 2400lbs. {max.2550cc}

9.  All weights are before qualifying and after the race.

10.  Driver must post their claimed weights at all times on the top left corner of windshield in 1.5″ tall numbers.  Numbers must be easily visible to HS officials.  White vinyl numbers are preferred.

11.  No fuel burnoff allowance.

12.  Any car competing with an engine other than a Toyota or Ford must be preapproved by HS Official and may be subject to a penalty change at any given time.


1. Steel, aluminum, or fiberglass body allowed but must follow all weight penalties. 

2. Must have 4″ ground clearance, body and frame included, with driver and safety equipment, before and after the race. 

3. Full Front windshield required, must be 1/8” Lexan/Polycarbonate. No plexiglass.  Must allow 5” at op of windshield for division sponsor sticker.

4. Rear window permitted.

5. Rear body panel must cover rear of car to bumper.

6. Tread Width 64″ measured from true center of tires at spindle height. Zero tolerance.

7.  Car must not have any sharp or pointed edges that could harm or injure the driver, tech official or safety crew.

Rear Spoiler

1. Maximum 6″ in height x 60” width. May not exceed the width of body and cannot be mounted past rear quarter panels.

Stock OEM Chassis

1.  Stock OEM mini chassis is classified as:  Toyota Corolla, Ford Pinto, Ford Mustang II.  Any other make and model is classified as full tube frame.  All chassis must be rear wheel drive and approved by Huntsville Speedway before competing.

2. All components must remain stock, as produced by manufacturer and mounted in stock location, unless specified. Front and rear sub frames may be connected with tubular framing. One piece per side. Location optional. May “X” frames or add cross members.

3. Stock type sway bars only. No spline bars allowed.

Wheel Base Dimensions

1.  93” minimum to 108” maximum


1. Any steel body non-adjustable shock allowed.

2. Schrader valve shocks not permitted.

3. Bump stops are permitted.

4. Aluminum non-adjustable shocks allowed with a 20 lbs penalty.

5. Post Race Shock Buy Out – $125/per shock claim rule. Buyer must buy all four shocks at time of protest.  All four shocks must be delivered to tech official undamaged and fully functional.   Any driver that does not submit to the claim rule will be Disqualified, NO Points, NO Money. Also, they will not be allowed to bring those shocks back at any time.


1. Any coil spring may be used except coil binding springs.  (front minimum 3 1/2″ rear minimum 2″)

2. Wedge bolt adjusters allowed.

3. Only stock main leaf spring for make and model of car permitted. Number of leafs optional. May use clamps. May cut secondary leaf. Sliders permitted with wedge bolt adjusters.

4. Strut cars may use tech approved coil-over adjusters on front only.

5. May elongate slots for caster/camber adjustments.


1. Steering box and components must be stock and in stock location.

2. Adjustable rack & pinion allowed.


1. Front and rear disc brakes permitted. Aftermarket brake parts allowed with a 30 lbs penalty.

2. Any aftermarket pedal assembly or aftermarket master cylinder set up permitted with no weight penalty.

3. All four wheels must have working brakes.


1. Any stock passenger car rear-end must remain in stock location, centered in car. No offset.

2. Differential may be locked.  Differential may have either welded, mini spool or stock OEM positive traction or open rear end (no Detroit or any other center section that has not been specified.)  No quick change. No cambered rear-ends. No gold tracks. No aluminum spools.

3.  Floating axles are permitted.

Drive shaft

1. Driveshaft must be made of steel. NO Aluminum driveshafts! No aluminum parts of any kind in the driveline.

2. Must have at least one HS approved safety loop around driveshaft. Driveshaft must be painted white.


1. Any stock transmission permitted.  Automatic transmissions must have working torque converter.

2. All transmissions must be stock OEM and unmodified. Must be in working condition with reverse and all forward gears.

3.  1 inch inspection hole in bellhousing recommended for tech officials.

Clutch/ Pressure plate

1. Stock diameter clutch and pressure plate. No aluminum parts.

2. May run solid center or button style clutch disc.

Manual Flywheel

1. Aftermarket flywheels permitted. Flywheel must be stock diameter- minimum weight 11 lbs. including flywheel bolts.

2. NO Aluminum flywheels allowed.

Fuel/ Fuel Cell

1. Fuel cell is mandatory, 12 gal. maximum with foam, must have check valve and mounted in trunk area inside a metal box and must also have firewall between fuel cell and driver.

2. 8″ ground clearance.

3. It is recommended that fuel cell should be located as far forward as possible, but stay behind the differential housing. Fuel cell must be between frame rails with proper ground clearance and secured with two 1/8” x 2” steel straps or four 1/8” X 1” steel straps and must be approved by HS officials. Fuel cells must be bolted. No rivets and no sheet metal screws.

4. Location of fuel cells must be approved by HS tech inspectors.

5. Must run Huntsville Speedway 110 octane racing fuel. (ie No E85, alcohol, or oxygenated fuels or additives of any kind)

6. Fuel must go through the fuel cell to the carburetor and cannot pass through any performance enhancing/cooling devices.

7. Electric fuel pumps permitted with a manual fuel pump cut off switch in the reach of driver and automatic oil shut off switch.

Abide by all general rules!!