This Music City Motorplex Division will compete under the sanctions of NASCAR. The specifications listed will become part of the official NASCAR rulebook, except in cases of obvious conflict. All technical rules will generally fall within NASCAR and Music City Motorplex specifications. NASCAR officials will resolve any disputes. All drivers in this division must be members of NASCAR and Music City Motorplex to compete.

NOTICE:  All equipment is subject to the approval of NASCAR officials. No equipment will be considered as having been approved by reason of having passed through inspection unobserved. Any equipment which does not conform to specifications or tolerances contained in this NASCAR rulebook, will not be eligible for approval.

NOTE:  All cars must comply with the rules set forth by the Music City Motorplex rule book to be eligible for competition.  Any and all cars and car parts are subject to MCM technical inspection processes.  MCM is not required to follow any other sanctioning bodies or manufactures guidelines in its inspection processes.

1.             WHEELBASE and ELIGIBE MODELS

1.1  Any stock appearing, 1995 or older U.S. made sedan or hardtop car.

1.2  Station wagon or El Camino style bodies not allowed.

1.3  No Mustangs, Camaro, Firebird or similar types.  No late model style bodies allowed.

1.4  Wheelbase: Car must be minimum of 108”. No altering or cutting down frames.

1.6  Maximum tread width 64” (+ or – ½”) measured center to center of tires at spindle height (front and rear).

2.             BODY and APPEARANCE

2.1  Stock body configuration and appearance must be retained.  No alteration of produced angles, heights.

2.2  Must be metal or aftermarket bodies, stock appearing.  Aftermarket bodies must meet ARP guidelines.

2.5  All bodies must be located in stock appearing  configuration.

2.6  Approved fiberglass hoods and trunk decks will be allowed.  Minimum of six (6) hood pins required.

2.7  No open hood scoops.

2.8  No type of aerodynamic devices allowed.

2.9  Floor pan must remain intact in driver’s compartment. If repaired must min. be 22 gauge steel.

2.10  Door panels, replaced with a 22 gauge steel minimum must meet stock configuration, size and appearance.

2.11  Windshield posts and cowl must remain stock appearing, rigid and intact.

2.12  Front firewall and outer cowl panel must remain as produced for make and model with no alterations and in stock location.

2.13  Front firewall holes must be sealed with steel.

2.15  Driver’s compartment must be completely sealed from trunk and rear wheel wells.

2.16  Interior tin kits are not allowed.

2.17  Roof heights must be within one (1) inch of stock production.  Measured from top of frame rail.

2.18  Grill may be replaced by stock appearing screen.

2.19  All exterior body holes must be covered by metal.

2.20  Replacement of rust damage allowed on quarters and fenders below centerline of bumper area, OEM shape and appearance must be retained.

2.21  Bumpers must be welded to frame in stock location.

2.22  Wheel wells may be enlarged for tire clearance, but may not exceed three (3) inches.  Tires may not protrude outside of body.  No fender flares allowed.

2.23  Rear spoilers mandatory.

2.24  Rear spoiler must be mounted on the trailing edge of the stock trunk deck, mounted in normal position, within ½ of center of rear deck lid.

2.25  Spoiler may not exceed six (6) inches in total height.  Must be single plane only.  Maximum width 58”.

2.26  Rear spoiler minimum height of 38” measured from center of deck lid to ground. No braces allowed.

3.             WINDSHIELD and GLASS

3.1  Front and rear windshields mandatory.  Recommended is 1/8” Lexan with a minimum if two (2) center braces required and at a stock angle.  No Plexiglas

allowed.

3.2  No type of window or air deflector allowed.  Side vent “roll over” may not exceed ten (10) inches at lowest point and must continue 90 degrees upward

from that point.  NACA duct for driver fresh air allowed.

3.3  No tinting of front, rear vent or rear windows.

4.             ENGINE LOCATION

4.1  Engine must be centered between frame rails.

4.2  Maximum engine set back will be the #1 spark plug (front left plug) even with lower ball joints on lower A-frame at any time with zero caster degrees.

4.3  No motor plates.

4.4  The lateral location (side to side) measured from the cylinders to center of front control amounts must be equal.  Engine must be centered within ½”.

5.             ENGINE GROUND CLEARANCE

5.1  A minimum of twelve (12) inch from centerline of the crankshaft, in the front to the ground must be maintained.

6.             ENGINE DISPLACEMENT

6.1  Ford and Chevy may not exceed 358 cid. Chrysler may not exceed 360.

6.2  Overbore of .060 maximum. 

7.             ENGINE BLOCK

7.1  Must be of standard factory production with standard external measurements in all respects.

7.2  No plastic or aluminum blocks.

8.             ENGINE PISTON and RODS

8.1  Flat top pistons only.

8.2  Piston may be flush with block (zero deck height).

8.3  OEM or steel connecting rods permitted (must be magnetic).

8.4  Rods must match engine size (example 5.700 inches on 350 Chevrolet).

9.             OIL PANS and OIL SYSTEMS

9.1  Seven-quart oil pans allowed.

9.2  No remote oil systems or filters.

9.3  One stock type oil filter in original location.

9.4  No oil coolers, accusumps or additional oil lines permitted other than line to oil pressure gauge.

9.5  On altered oil pans, one ¾ inch, pipe plug inspection hole must be installed for inspection purposes to reveal a rod journal.

10.          CRANKSHAFT and BALANCER

10.1  Standard production crankshaft only.         

10.2  No 180-degree, scalloped, knife-edge crankshafts.

10.3  Stroke must be stock stroke within .010, may not be increased or decreased.

10.4  Stock type or any S.F.I. approved balancers only. No titanium or aluminum.

10.5  Fifty-pound minimum weight on all crankshafts, including timing chain gear.

11.          CYLINDER HEADS

11.1  The cylinder heads must be completely cast iron, the intake and exhaust ports must be in the original “as cast” configuration. Stock Heads Only.

11.2  Minimum 64 cc combustion chamber.

11.3  Mopar products: maximum 1.624 in exhaust, maximum 1.920 in. intake valves.

11.4  Ford Cleveland: maximum 1.655 in exhaust, maximum 2.041 in. intake valves.

11.5  Ford Windsor: maximum 1.546 in exhaust, maximum 2.041 in. intake valves.

11.6  Chevrolet small block: maximum 1.500 in exhaust, 1.940 in. intake valves.

11.7  No Dart, Vortec, angle plug, L31, 461, 461x, 462, 492 or “bowtie” heads allowed.

11.8  World Products SR 043610 stock replacement heads (1.5 / 1.940) allowed.

11.9  Altered heads will be confiscated.

11.10  Stock appearing, steel magnetic valves and in stock location only.

11.11  Stock diameter valve spring with steel retainers only. Chevrolet maximum 1.25”

11.12  3 angle valve jobs permitted, however no machine or stone marks or blending of angle,  past the chamfer into the bowl area.

11.13  Screw in or pinned rocker studs are allowed.

11.14  No titanium parts. Locks and retainers must be magnetic steel.

12.          INTAKE MANIFOLD

12.1  All engines must have stock unaltered production single carburetor, cast iron intake manifolds.

12.2  Manifold origin must be an EGR type street application only.

12.3  No aluminum, “Bow Tie” or high performance intakes allowed.

12.4  No alterations permitted to manifolds Except:

           A.  EGR Hole may be plugged.

           B.  Top plenum casting void may be epoxy filled.

12.5  No porting, polishing, cutting, coating or painting allowed.

12.6  On all engines, only one standard flat gasket may be used between the head and the intake manifold. Maximum gasket thickness .177 inch.

12.7  No wedge type gaskets, metal or Bakelite spacers allowed.

12.8  Intake manifold ½“ water-cooling kit allowed.

12.9  Any attempt to pull outside air in not permitted.

13.          CAMSHAFT, VALVE LIFTERS and ROCKERS

13.1  Only hydraulic flat tappet cams and stock hydraulic magnetic lifters are allowed.

13.2  Maximum valve lift may not exceed .450. 

13.3  Camshaft lift checked with solid lifter with zero lash at retainer of valve.

13.4  Stock appearing, stock size valve lifters only.

13.5  Lifters must be of stock diameter for engine application.

13.6  No mushroom or roller type lifters or camshaft.

13.7  No roller rocker arms permitted. No girdles.

13.8  1.5 ratio rockers only. Cool nuts permitted.

14.          EXHAUST

14.1  All competing cars must have a working exhaust system that meet a maximum of 100 dba at 100 feet under racing conditions. No Exceptions.

14.2  Economy 1 5/8” headers with no steps, allowed with a 3” collector into single 3” pipe that exits under car past driver.

14.3  No alterations of any type, except external modifications for clearance purposes only, without any spacers or adapter plates.

14.4   X or H pipes are not allowed.

14.5  No flexible pipes allowed anywhere or anytime.

14.6  No thermal wraps, coatings or painting allowed.

14.7  Mufflers must be unaltered internally ( not gutted ).

14.8  All Grand National Sportsman will be permitted a 5/16 header flange max with no spacer of any kind between the head of flange.

14.9  Exhaust gasket may not exceed .090 compressed.

14.10 Mufflers are required, recommended mufflers are Schoenfeld #112530 or #113035. However muffler price must not exceed $100.  Muffler may not be             altered internally.

15.          CARBURETOR

15.1   See Section 9

16.          CARBURETOR SPACERS, GASKETS and MOUNTING

16.1  Adapter plate must be made of metal only.

16.2  Carburetor gasket, maximum of .060”, must be pliable paper gasket material.      

16.3  One (1) inch maximum spacer allowed between air cleaner bottom and carburetor for linkage clearance issue only.

16.4  Recommended minimum of two (2) return springs (opposing each other).

16.5  Throttle stops highly recommended.

16.6  Machined Engines only a 1 piece, solid, aluminum carburetor spacer, a minimum 0.700 inch, maximum 0.750 inch in thickness, must be installed

between intake manifold and carburetor.  The spacer must be centered on the intake manifold and have two (2) round holes with one and one-half (1 ½”) inch openings located in the center that match the base of the carburetor. Holes must be cut perpendicular with the base of the carburetor.  Taper, bevels, or any modifications will not be permitted.

16.7   Crate Motors carb spacer #CV156 only, no modifications of any kind permitted. 

17.          AIR INTAKE

17.1  No air boxes allowed. No air dams, ram air or duct systems allowed.

17.2  Only one dry paper air cleaner element or less allowed.

17.3  No addition of material, shielding or alterations of air flow to air cleaner.

18.          FUEL SYSTEMS

18.1  Racing fuel cells are mandatory, bladder type cells are highly recommended.

18.2  Maximum 22-gallon cells with fuel check valves.

18.3  Loop bar mandatory behind fuel cell.

18.4  Two (2) sections of box tubing may also tie the rear frame rails together and act as a fuel cell mount.

18.5  Fuel cells must be in trunk compartment, equal distance between frame rails and centerline of car.

18.6  Bottom of fuel cell container must have a minimum ground clearance of 8”

18.7  Stock type mechanical fuel pump only, in stock location. No electric fuel pumps allowed.

18.8  No additional fuel reservoir, pressure equalizing systems, or fuel cooling devices allowed.

18.9  No cooling of fuel or engine with ice or any substance before qualifying or before race.

19.          ELECTRICAL SYSTEMS

19.1  HEI ignition only

19.2  One stock coil, ballast resistor if applicable, or absolutely stock electronic ignition distributor.      

19.3  No made for racing distributors, racing coils, multiple discharge systems, crank trigger or distributor less systems allowed.

19.4  No brass gears or printed circuit modules.

19.5  Stock style starters only.     

19.6  The alternator system, when used, must be mounted to front of the engine in the standard location and must not exceed 14.9 volt output single wire

system.

20.          COOLING SYSTEMS

20.1  Any metal stock production or racing radiators permitted in stock location.

20.2  Fan must have a 180-degree shroud. Covering the top 50% of the fan.

20.3  Mandatory and operational radiator overflow metal catch can and exit tube installed ahead of firewall.

20.4  No electric fans.

20.5  Front air shroud may not extend more than 2” below bottom edge of bumper and exceed width of radiator.

20.6  Aluminum water pumps are allowed.

20.7  No antifreeze allowed at any time $250 fine.   

21.          CLUTCH

21.1  Manual transmission must utilize stock all steel type pressure plate and steel or cast iron flywheel 14 inches only, 168 tooth, standard.

21.2  10.5 inch pressure plate minimum 13.5 pounds, disc 10.5 inch only, 6 rigid friction pads minimum, minimum 3 pounds total weight.

21.3  Pressure plate must be of stock configuration.

21.4  Hydraulic clutch linkage permitted.

21.5  Cars must provide inspection holes for clutch or torque converters.

21.6  Blow proof bell housing, stock clutch and stock flywheel are mandatory.

21.7  Stock, steel flywheel only. No lightweight or altered stock flywheels.

22.          TRANSMISSION

22.1  Transmission options:                                                                                                                                                                               

           A.  Stock OEM automatic with minimum of 3 forward gears.

           B.  Manual cast iron case OEM with all gears operable.

22.2  No 4 or 5-speed transmissions.

22.3  No internal modifications or gear reductions are allowed.

22.4  Stock, for make and model, automatic transmissions with unaltered torque converter allowed. No direct drives.

22.5  Transmission coolers allowed in engine compartment only.

22.6  Automatics must have complete unlightened factory produced flywheel or flex plate.

22.7  Single lever shifter must be stock type.

23.          DIFFERENTIAL

23.1  Stock production rear ends for that chassis manufacturer allowed.

23.2  9” Ford with drum brake assembly allowed with all brackets in stock location for that chassis.

23.3  Only open, locked, limited slip or posi-traction rear ends are acceptable.

23.4  No quick changes, Detroit Lockers or “gold track” type differentials.

23.5  No full floating type axle assemblies allowed.

23.6  Aftermarket racing axles are recommended.

24.          DRIVERLINE

24.1  Two (2) 360-degree drive shaft “2” x ¼” hoops” mandatory, installed on forward 3/5 of drive shaft.

24.2  One-piece steel drive shafts only. (min. dia. 2 3/4”.)

24.3  Drive shafts must be painted white.            

25.          BRAKES

25.2  Brake pedals must follow stock configuration.

25.3  Must have functional brakes on all 4 wheels at all times.

25.4  Rear brakes must be drum style.

25.5  No brake bias devices allowed.

25.6  Single piston calipers, with cast iron bodies only.

25.7  Brake pad material optional.

26.          FRAMES and UNIBODY

26.1  All frames and unibody structures must remain absolutely OEM factory produced.

26.2  All measurements for all vital parts must remain stock. Body must be centered on frame.  

26.3  Replacement of rear frame rails with 2”x 3”x .120 minimum wall, steel tubing, permitted rearward from the center of the rear wheel hump.

26.4  Frames and unibody structure may not be lightened anywhere.

26.5  Frame spacers must remain stock and in stock location.

26.10  Bodies may only be bolted to frames at original body mount locations.

26.13  Front frame horns may be tied together by a maximum 1 ¾ “ tubbing not to extend past front frame horns.  Must be located in front of radiator.

26.14  No chopped down frames.

27.          ROLL BARS

27.1  All cages must be NASCAR style as set forth in the NASCAR rulebook and approved for workmanship and design.

27.2  Driver is responsible for installation, construction and workmanship of roll cage.

27.3  Round steel 1 ¾“ x .083 minimum, roll bars are mandatory, roll bars must be welded. 

27.5  Minimum of four horizontal door bars on the right and left side of car.

27.7  The distance between the “A” post and “B” post may not be greater than 44 inches. 

27.11  Rear fuel cell protection hoop mandatory.

27.12  Gusset plates at butt welds in driver’s compartment required.  Rear frame rails may be tied together by only one 2 “ x 2 “ max. bar only.

28.          SUSPENSION

28.1  All front suspension mountings and spring locations must remain as produced except A-frame mounting may be replace with “perch” type mounting.

28.2  Front shock location may be changed from stock location.

28.3  Sways bars must be in stock location, with adjustable mounts permitted.  “U” bolts permitted.

28.4  After-market sway bars allowed, must be stock appearing,  1 1/2” maximum diameter allowed.

28.5  Any conventional type coil front spring with a diameter of 5” or greater can be used.

28.6  Wedge bolts are allowed front and rear, maximum one per wheel, top adjustable only.

28.7  Spring pocket of stub may not be altered other than to screw plate installation.

28.9  Lower control arms must be stock and unaltered for that make and model.

28.11  Upper magnetic steel tubular A-frames or altered stock upper control arms utilizing stock A-frame permitted, however heim joint ends are not allowed.

28.12  Any ball joints with steel shaft allowed.

28.13  Steel shocks only, may be revalvable and/or adjustable, not exceeding $175.00 net price, available at normal retail outlets.

28.14  No Schrader valves

28.15  One shock per wheel.

28.16  Rear shock upper mounts must be inside frame rails.

28.17  Rear shock mounts on rear axle may be raised or lowered to compensate for rear shock travel.   

28.18  Rear suspension must be as produced, either leaf or coil. Adjustable rear shackles allowed on rear leaf springs only.             

28.19  All rear suspension parts, mountings and location must remain stock and unaltered. Bushings optional.

28.20  No sliders on leaf springs.

28.21  Shocks may be claimed after event for $175 each, by any driver finishing behind claimee, first come first serve basis.

29.          SPINDLES / HUBS

29.1  Any stock passenger car spindle may be used. No drop spindles

29.2  Heavy duty aftermarket spindles allowed, but no racing spindles.

29.3  Any stock car hub, drum and rotor may be used.

29.4  Large diameter wheel studs acceptable.

30.          STEERING

30.1  Conventional steering systems consisting of stock steering gear and pitman arms, idler arms, center link, and tie rods are the only type allowed.

30.2  Stock systems either manual or power. No alterations.

30.3  Stock rack and pinion with no modifications allowed when stock on that car.

30.4  Quick release hubs recommended.

30.5  Steering ratio may be changed only within steering gear box.

30.6  Chrysler may use “in-line” steering quickeners.

31.          GROUND CLEARANCE

31.1  Suspension and frame, at any point of frame rail, must maintain an absolute minimum ground clearance of six inches (6”) at all times.

31.2  Parts of car that are factory produced at greater than six inches must remain at proportionate clearance.

31.3  4.5” is the minimum clearance for all parts including cross member but excluding exhaust and oil pan.

31.4  Fuel cell must have a minimum ground clearance of eight (8”) inches.

31.5  Dragging exhaust systems will result in immediate black flag.              

32.          WHEELS

32. 1  Minimum wheel weight of 19 lb. - IMCA “sticker” legal.

32.2  Acceptable only are steel wheels with a maximum width of 8” inside bead to bead.

32.3  Reinforced race type wheels are mandatory.

32.4  Wheel offset may not exceed a maximum of 1” of each other.

32.6  No bleeder valves allowed. 

33.          TIRES (Section 11)

33.1  Tires must be purchased and verified through Music City Motorplex Tire Sales only.  Receipts will be required.

34.          WEIGHT

34.1  Management reserves the right to alter, change or adjust weight limits at their option and add additional weight to non-conforming cars.

34.2  Minimum weight at any time: 3,200 lbs.

34.3  Right side weight at any time will be at least 1,470 lb.

34.6  Weight boxes optional, constructed of minimum 3” x 3” x .120 square steel tubing and must be welded completely to frame.

34.8  All weight must be painted white or fluorescent color with car number written clearly in black or red.

35.          FUEL CELL INSTALLANTION

35.1  See section 19 for details

36.          PERSONAL PROTECTION REQUIREMENTS

36.1  See section 7 for details

37.          ELIGIBILITY

37.1  See section 1 and 3 for details

38.          GENERAL POLICY

38.1  See section 3 for details

38.2  Spotters are mandatory

39.          NUMBER and APPEARANCE (Section 7)

39.1  See section 7 for details

40.          TYPES OF RACING EVENTS (Section 3)

40.1  See section 7 for details

41.          CLAIM RULES

41.1  Claims and claim procedures; protest and questions must be addressed to Director of Competition.

41.2  See shock claim 28.21