2014 Limited Modified Rules

 

 

RULES/INSPECTIONS:

A) All cars are subject to a safety and technical inspection at any time at the track. Approval of a vehicle by a track inspection means only that the vehicle is approved for participation in a racing event and shall not be construed in any way to mean the inspected vehicle is in a mechanically safe and sound condition. Officials can disqualify any car or driver for any perceived unsafe equipment or actions.

B) Uniform interpretation of these rules at all tracks will be insured by designated track officials.

C) By competing in USA events, a driver agrees to comply with these safety and technical rules and

any additional local track rules.

D) The rules set forth herein are only designed to provide for the orderly conduct of racing events and to establish minimum acceptable requirements for such events. No expressed or implied warranty of safety shall result from publication 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 participants.

SAFETY:

A) Main roll cage (halo and four down tubes) must consist of continuous hoops not less than 1-1/2” O.D. and an inner wall thickness of no less than .095”. Must be welded to frame—no  brazing—no soldering. No part of the main cage can extend farther forward than the engine plate.

1. Must be frame-mounted in at least six places, securely supported and cross braced.

2. Must consist of a configuration of front and rear hoops connected by tubing on the sides or side hoops. The top hoop must have a crossbar and the driver’s head (with helmet on) must not protrude above the cage. Padding required on tubing around the driver.

3. Protection of driver’s feet is mandatory. Bar across the back of the engine with vertical bars and

rub rails or similar protection.

4. Brace bars forward of the cage cannot be higher than a stock hood height.

5. Driver door bars must be at least three 1-1/2” O.D. bars which are welded directly to the front

and rear members of the main roll cage. Bars must be parallel to the ground and perpendicular to the

driver to provide maximum protection but without causing undue difficulty in getting into or out of

the race car. Door plates recommended and can be required by local tracks

B) Helmet must be Snell SA90 or SA95, and must be worn at all times the car is on track. SFI- approved full fire suits, fire-retardant neck braces and fire-retardant gloves must be worn while in competition. Fire-retardant shoes are recommended.

 

C) Competition five-point safety belts, sub belts and shoulder harness required. Metal to metal

buckles required on shoulder and seat belts. Shoulder harness must be securely mounted to the roll cage at a height even with or above the driver’s shoulders. Belts and harnesses recommended to be no more than one year old.

D) Either arm restraints or a driver-side window net is required. The window net will be mounted to place the latch at the top front of the driver-side window.

E) Both side windows of the car must have at least a 12-inch vertical opening to allow easy entry and exit from the car.

F) All cars must have fuel cells (maximum 32 gallons) enclosed in a metal container. Fuel cells must be mounted between frame rails, secured with at least two 2” wide steel straps, be mounted securely behind rear axle (protected by roll cage tubing) and be at least 4” forward of the trailing edge of the rear bumper. Fuel cells must have check valves and fuel pick-up from the front, side or top of the

cell. Bladders are recommended.

G) Protective tubing (fuel cell loop) must cover the rear of the fuel cell with no part of the fuel cell extending below or to the sides of the loop. Loop cannot be wider than leaf spring shackles. No part of the loop can extend past the trailing edges of the rear bumper.

H) Batteries must be securely mounted and shielded. Batteries mounted inside the race car must be in marine-type cases.

I) Exhaust systems must be mounted in such a way as to direct exhaust away from driver and areas of

possible fuel spillage. The driver’s compartment must be sealed from the track and exhaust gasses.

J) Loose objects must not be used in the driver’s compartment nor outside the car body, nor the hood area. Any weights added to other areas of the car must be inside the car body — not attached to the

bumper or fuel cell loop. Such weights must list the car number, be painted white or silver and must be mounted with at least two 1/2” bolts.

K) Drive shafts must be painted white or silver and have a loop mounted no more than six inches from the front of the driveshaft. The loop must be constructed of 1/4” thick by 2” wide steel stock, or equivalent, and must totally encircle the driveshaft (360 degrees).

L) All transmissions with clutch mounted to flywheel require steel explosion-proof bell housing. All other transmissions (manual or automatic) must have SFI approved flywheel shield. (Shield can be constructed of 1/4” x 3” steel, 270 degrees around flex plate/flywheel.)

M) Brakes must be operable and must lock-up three wheels during an inspection. Shut-off valve is

allowed on right front brake. Front-to-rear proportioning valves and/or brake bias systems are

allowed.

N) Ignition (“Kill”) switch must be within easy reach of the driver and must be clearly marked “ON-

OFF”.

O) Each car must have a 5-pound (minimum) fire extinguisher in the immediate pit area.

 

 

LINE-UPS:

A) All race line-up procedures are determined by the track. USA recommends no more than 10 cars in any hear race.

B) Race car must be capable of starting to join the line-up, without being pushed or pulled, or goes to rear of the line-up.

 

 

PROTESTS:

A) Protests must be specific, in writing and filed with the designated USA track official before the A feature starts. The protest fee of $100 cash must accompany the protest filing. For protests which require a “tear-down” of transmission or differential, the protest fee is $200.

B) After the feature the protested car driver will be informed and the specific item (s) will be checked.

 

 

 

C) When a protest is upheld (the technical inspector is the sole authority) and the violation provides a distinct competitive advantage, the car will be disqualified and the fee will be returned.

D) When a protest is denied, half the protest fee is awarded to the protested driver and half is retained by the track.

FRAME:

A) 1978-1987 OEM midsize GM metric full frame only. Minimum wheelbase 107-inches, maximum

109-inches, both sides. Frame must be full and complete, cannot be widened, narrowed, shortened,

lengthened, or be cut, bent, or altered to change suspension brackets, except upper control arm brackets on front end. All frame bolt holes must remain in OEM location. Front frame horns may be removed in front of steering box. Front frame may be cut for radiator clearance. Frame may be notched for seat clearance. Transmission cross member mounts may be removed, no further

forward than frame welds. Rear of frame, behind upper shock mounts, may be replaced with round, square, or rectangular tubing. No part of frame can be lower than five inches from ground except front cross member. No other frame alterations allowed.

 

 

ROLL CAGE:

A) Must consist of continuous hoops, minimum 1.5 inch O.D. tubing, with a minimum wall thickness of .095 inch for main cage. Cages must be steel or chrome-moly. Main cage no further forward than rear of engine and no further back than front edge of rear tire. Four bars, two per side, may extend from main roll cage to main frame points in front of the upper control arms. These bars may have two additional braces per side to the main frame. Six bars may extend from the main cage to the

rear. X-bracing  is allowed. Driver’s  head must not protrude outside cage with helmet on. Roll cage

must be securely supported and braced with minimum one cross bar in top halo. All bars forward of

cage must be lower than hood.

 

 

DOOR BARS:

A) Minimum three driver side door bars required, minimum 1.5 inch O.D. and .083 inch wall thickness, must be parallel to ground and perpendicular to driver, and welded to front and rear of roll cage. Minimum two passenger side door bars required, must have at least one cross door bar, horizontal or angled. Steel door plate, 18 gauge or .049-inch minimum thickness, must be securely welded to outside of driver side door bars and cover area to protect driver.

 

 

BODY: (See diagram on next page)

 

A) Must be same width, front to rear, and parallel to OEM frame. Engine compartment must remain open (no side panels). Aluminum or fiberglass hoods allowed must completely cover top of radiator and engine, extending from nose to interior deck and enclosed at rear. Must have front and rear roof supports. No Gremlin roofs. No plastic body panels or filler panels allowed. Must have complete interior deck from side to side, must be aluminum or sheet metal. Quarter panels must remain 90-degrees to ground, maximum 45-degree bend 4-inches from bottom and 2-inches from top of doors and quarters. Rear spoiler may be maximum 8 inches in material height and maximum

67 inches wide. Spoiler may have stiffener, must be 1 inch or more down from top. Maximum 3 spoiler braces allowed, must be mounted in line. Spoiler braces must resemble all aspects of drawing. No fins, lips or wings allowed.

USA Limited Modified

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DRIVER COMPARTMENT:

A) Must have minimum three 5/16 inch O.D. windshield bars in front of driver. Aluminum cowl panel in front of driver can be no wider than cockpit. Aluminum high-back seat only, must be securely bolted, using minimum 0.375-inch bolts, to roll cage and support system. Floor pan must be metal or aluminum and cover entire driver compartment. Bottom of seat can be no lower than bottom of frame rail. Driver must be sealed off from track, driveline, engine, fuel cell, canisters and pumps. No oil coolers allowed in driver compartment. No devices that would enable driver adjustment to alter wheelbase or for weight jacking while car is in competition. No mirrors of any kind.

 

 

SUSPENSION/STEERING:

A) STEERING: All components must be steel, unaltered OEM, in OEM location and match frame.

No grinding, lightening or welding on any steering parts. Spindle may be reamed and bolt on

spindle savers are allowed. Steel steering shafts and knuckles only. Steering Quickeners (optional), steering wheel and quick release (required) may be aluminum. Power steering pump and reservoir must remain one unit. Driver compartment steering may be modified, must be kept on left side. No rack and pinion.

B) SHOCKS: One steel shock per wheel only. Shock must be in OEM mounts and location using

OEM style shock. Mounting spacers and weld or screw-on shock ends allowed. No air or coil-over

shocks, remote reservoir shocks, Schrader valves or refill ports.

C) SPRINGS: One steel spring (racing allowed) per wheel only. Minimum 4.5-inches O.D., non-

progressive coils only. No torsion bars or air bags.

 

 

D) REAR SUSPENSION: All control arms and mounts must be steel, unaltered OEM, in OEM

location, and match frame. No jack bolts allowed. Adjustable spring buckets allowed, may be

dropped as long as they remain in OEM location. If upper spring cup uses all thread, it must be securely welded to chassis. Lower spring cups must be centered on housing. Control arms may be reinforced, but cannot be shortened or lengthened, must remain OEM length. All control arm bushings may be aftermarket, but no bearing/heim type. No suspension parts may be altered or lightened. No aluminum parts allowed, other than bushings.

E) FRONT SUSPENSION:  All components must be steel, unaltered OEM, in OEM location, and match frame. No jack bolts allowed. Adjustable spring buckets are allowed. Must use OEM upper and lower A-frames and mounts. OEM upper A-frame may be replaced using aftermarket upper A-frame (STEEL only). Upper A-frame mounts may be modified and moved for caster and camber adjustment, but must remain OEM material. Lower A-frame mounts and bolt holes on frame must be in OEM location, mount may be notched for clearance. All A-frame bushings may be aftermarket, but no bearing/heim type. OEM style ball joints only, may be tacked in. Sway bars (optional) and brackets must remain OEM.

 

 

REAR END:

A) Must use OEM 7.5 inch GM 10 bolt rear end (bracing optional), must remain stock width. No Ford    

or floater rear end allowed. Housing end, from control arm mount out, may be modified with three                        inch tubing to accept nine inch Ford axle. If Ford axles are used, rear-end must remain minimum GM width or maximum three inches wider. Steel components only. OEM mounts on lower control arms must remain in OEM location on original 7.5 inch tube housing. Aftermarket axles, mini-spools and C-clip eliminators allowed. Locked rear ends only, no torque dividing differentials allowed. No full or aluminum spools allowed. Pinion angle cannot be changed. Any gear ratio allowed but housing must remain unaltered. No quick change devices

 

BUMPERS/RUB RAILS:

A) Steel only. Two bar front bumper and single bar rear bumper must be used on car at all times and welded, or bolted securely. Must be maximum 1.50-inch O.D. tubing, .095-inch wall thickness on front and 1.75-inch tubing, .095 wall thickness on rear. Maximum 1.50-inch O.D. tubing, .095-inch wall thickness fuel cell protection bar required, must cover rear and extend past both sides of cell, may be welded to rear bumper. See diagram for bumper heights. Rear bumper may be maximum 6- inches beyond rear deck. All bumpers and rub rails must be capped with no sharp edges. Single bar rub rail from front to rear wheel allowed on each side, no center supports allowed, maximum 1.50- inch O.D. tubing and .095-inch wall thickness, must be mounted to cage at front and rear of rub

rail.

 

 

 

TIRES/WHEELS:

 

A)  Must use Hoosier „500‟ Hard Race tire only, 27 by 8 by 15 or 26.5 by 8 by 15 „stagger tire‟ allowed (see rule book for automatic penalties). Tires may by ground and sipped within confines of tread.  Grooving allowed ONLY TILL JUNE 29 2013 after that date grooving will no longer be legal. No chemical softening or conditioning.  No re-caps. Must use 15”X 8” steel wheels. Any offset allowed. External steel bead lock allowed on right side only and it cannot make wheel any narrower than 8-inches and no wider than 8.75-inches. Foam or plastic mud covers allowed on right side only. Must use minimum 1-inch O.D. lug nuts and 0.625-inch studs are recommended. No wheel spacers allowed with OEM studs. Wheel adapters are treated as spacers and may be aluminum, maximum 1.50-inches thick. No bleeder valves. If you have any questions, please contact speedway office at 972-222-2421.

 

 

BRAKES:

A) Must be steel OEM, operative three wheel, drum or disc. Must maintain minimum OEM dimensions for hubs/rotors and calipers, cannot be lightened. Bolt pattern may be changed. 0.625- inch studs allowed. Single or dual aftermarket master cylinders allowed. Driver adjustable dual pedal brake bias allowed. Additional proportioning valve (in-line type) allowed, must be out of driver reach. Rear rotors may be aftermarket, minimum 0.810-inch thickness, maximum 12-inch O.D. Vented rotors only, no scalloped, single phase or drilled rotors allowed. Rear caliper brackets must be welded to housing.

 

 

EXHAUST / MUFFLERS

A) Must use Schoenfeld headers. GM: #161, #151, #151E with 1.625-inch tubes and 3-inch collector.

Chrysler: #461, #461W2, #462W2. Ford: #361, #362, #562, #562-4B #563-4B.  No header

modifications allowed. No exhaust sensors, cross over's, turn outs or balance tubes. Schoenfeld mufflers 609, 930, 935,  or 3 ring insert.  Dynatech – GM #701-16210, #701-10010.

FUEL SYSTEM:

A) Racing fuel cell required, maximum 22 gallon capacity must be in minimum 18 gauge steel container. Must be securely mounted, with minimum 2 steel straps around entire cell, between frame rails in trunk area only. Fuel cell vents, including cap vent, must have check valves. No part of cell can be lower than protective tubing. OEM mounted mechanical push rod fuel pumps only. No regulators, bypass fuel systems, pressurized, or return lines allowed

 

CARBURETOR (one only):

A)   Naturally aspirated, unaltered, 500 cfm Holley – part # 0-4412, may be modified to Holley HP   Dorton part no. 0-80583-1 specs only. Float bowl must face forward. Any adapter, maximum one inch thick. No throttle bore adjustable carburetor spacers.

FUEL:

A) Gasoline only. Racing fuel allowed. No performance enhancing additives or scented   additives.

Fuel must pass both dielectric meter and chemical tests. Fuel sample may be taken from any car at

any time.

 

 

MINIMUM WEIGHT:

Minimum weight limit of 2,350 pounds after race with driver in car. Weights must not be used in driver compartment or outside body. All weights must be securely mounted with at least two, .5- inch bolts, painted white with car number on it. No titanium, magnesium, stainless steel or carbon fiber components. Solid steel fasteners only.

 

 

BATTERY/STARTER:

A) One 12-volt battery only. Must be shielded and securely mounted. Aftermarket starter allowed, must bolt in OEM location. Must have capability of starting without being pushed or pulled. Must leave initial staging area on demand, unaided, or go to rear of that race.

 

 

GAUGES/ELECTRONICS:

A) OEM style ignitions only. GM: HEI distributor (must remain one unit) or point distributor allowed.

Ford/Chrysler: may use OEM ignition, including OEM boxes, or HEI distributor. Any module may

be used that fits inside the distributor with no alteration. Vacuum advance may be removed and pick-up coil locked. No external coils allowed, unless using point distributor. No GM or aftermarket ignition boxes allowed. No electronic traction control devices .

 

 

TRANSMISSION/DRIVE SHAFT:

 

A) Only OEM production transmissions allowed. No aftermarket transmissions allowed. No „in and out‟ boxes or quick change devices allowed. With engine running and car in a still position, must be able to engage car in gear and move forward, then backward. Functioning shift levers must be

in OEM location. Transmission fluid coolers allowed. Flywheel, flex plate and converter must be steel.

1) Automatic: Any OEM automatic transmission allowed. Must use functioning, minimum 10- inch diameter steel torque converter. No direct drives, couplers, valve pumps, or bleeder style

valve bodies. Must have at least one forward gear and reverse gear, gears must function. Must have

an approved scatter shield constructed of .125-inch by three-inch steel, 270 degrees around top of flex plate. GM automatic must be used with GM engine, may be used with Ford or Chrysler engine. Stall converters allowed. Steel OEM style flex plate only, must be bolted directly to end of crankshaft.

2) Manual: 3, 4 or 5 speed OEM manual transmissions only. All gears must function. Must have functioning 10.5-inch minimum diameter clutch and pressure plate bolted directly to steel

flywheel.  These components must rotate, consistent with engine rpm, while car is in any gear.

Must use explosion-proof, steel bell housing, 180 degrees around top of clutch and flywheel.

No mini-clutches or couplers. Minimum 9-inch diameter Ford clutch allowed. Hydraulic slave cylinder/throw out bearing allowed.

 

 

3) Drive Shaft: Minimum 2-inch diameter, white, steel drive shaft only. Steel slip-yokes only.

360-degree drive shaft loop required, constructed of at least 0.125-inch by 2-inch steel, or 1-inch

tubing, mounted 6-inches back from front U-joint.

 

POWER TRAIN:

A) Rear of engine (bell housing flange) must be mounted at least 70-inches forward from centerline of rear axle. Minimum 11-inch engine height from ground to center of crankshaft. One radiator allowed, steel or aluminum, 27-inches by 19-inches maximum in size, must be mounted in front of engine. Racing cap and electric fans allowed. No sprinklers. Catch can required. Power steering pump and reservoir must remain one unit and mount in front of engine. Side engine mounts (OEM or 45-degree style) must be steel, aluminum mid-plate allowed.

 

 

ENGINE SPECIFICATIONS:

A) Must use OEM cast iron, American make V-8 small block engines only. No bowtie, SVO or  W-2 components allowed. All engines must be able to be used in conventional passenger car without alterations. External engine casting and threaded holes cannot be altered. No aluminum, titanium or carbon fiber components allowed. BLOCK: GM (Chevy only): 283, 302, 305, 307, 327, 350.

Ford:260, 289, 302, 351. Chrysler: 273, 318, 340, 360, no hemi. Maximum cubic inch limits: GM 364 ci, Ford 360 ci, Chrysler 370 ci, no tolerance. No 400 or larger cubic inch parts allowed. Any flat top or dished pistons allowed, No gas ported or floating pistons. 3.48-inch maximum GM stroke. Maximum 175 lbs. per cylinder compression, no tolerance.  Compression checked with one spark plug removed, turned five engine revolutions. Engines may be balanced and block decked. Oil filter system must remain OEM. „Wet‟ sump oiling system only. No accusumps. OEM rods.

Chevy must use maximum 5.7-inch rod. OEM, or OEM replacement steel crankshaft and rods

only - cannot be lightened. No cap screws. Steel or cast OEM crankshafts only. No splayed main caps. Racing oil pans allowed. One inch inspection hole recommended in pan - no obstructions to crank and rods. If obstructions are present, must remove pan for inspection. Engine bolts may be aftermarket. Fluid dampener balancer allowed. No roller bearings allowed. INTAKE: Unaltered, approved OEM cast iron low rise, two- or four-barrel; or unaltered Weiand aluminum –

 ‘IMCA sta mp ed ’  Ch evr olet #7547 -1, Ford 302 #7515, 351 Windsor #8023, 351 Cleveland

#7516, Chrysler #7545, Edelbrock GM #2701. No porting, polishing, or alterations of any kind,   including cooling lines or plenum alterations to ANY intake. No OEM hi-rise, marine or bowtie intakes. Ford may use OEM aluminum intake, no under air or hi-rise.

B)  CAMSHAFT: No roller cam shafts. Solid or Hydraulic lifters allowed. No maximum cam lift. No alterations of any kind may be made at time of tech. Track equipment being used for tech is final. Lifter bores cannot be altered. Must be chain driven, no gear/belt drives. CYLINDER HEADS: Must use one of the following OEM GM cylinder heads (last 3 digits): 126, 185, 336, 441, 445,

487, 493, 598, 624, 862, 882, 920, 993,997, with valve no larger than 1.94-inch intake and 1.50- inch exhaust. Any cast iron OEM Ford and Chrysler heads allowed with valves no larger than 2.04- inch   intake and 1.70-inch     exhaust. Headers must bolt directly to heads with correct

numbers. No vortex, bowtie, SVO, W-2 or aftermarket heads allowed.  May use Engine Quest (EQ) Stock Replacement (SR) cylinder head, part number CH350I, head must remain as produced, valve sizes can not be changed. No porting, polishing, or unapproved alterations to ANY cylinder head. No porting, polishing, or alterations to heads of any kind. Flat milling allowed. Guide plates, screw-in