Smith Chevrolet "B" Modified Rules

Click here to print your copy of these rules.

Recent changes are highlighted in orange text.

2013 Tri-State Speedway Smith Chevrolet “B” Modified Rules

This is a USRA "B" Modified sanctioned class.

FRAMES

  1. Factory production complete full American passenger frames only. Frame rails must extend to a point beyond the base of driver's seat. Rear clip may be fabricated out of tubing. Front and rear pick-up loop required; otherwise bumpers or other pick-up point will be used.

BODIES

  1. Same as A-Mod bodies. Exceptions: no spoilers, no spoiler sides, no nose wings.
  2. Bodies: The right side passenger side of the car the tire should be the widest point of the car, the body should not extend out past the tire. The left side driver’s side of the car the body may extend 1" past the tire.
  3. Rear Sail Panels: Must extend from the roof to the rear of the car and be the same on both sides.  4" max at rear, gradual slope from roof to this point. 1" max curve in center. Sail must be flush at the rear deck & may angle back no more than 2 “ past the deck at top of the sail at the 4" mark.

    WHEEL BASE

    1. 108 inches minimum. 112 inches maximum both sides.

    ROLL CAGE

    1. Must consist of continuous hoops not less than one and one-half inches outside diameter and must have a wall thickness of at least .095”. Must be frame mounted in at least six (6) places. Body mounted roll cages not acceptable.
    2. Must consist of configuration of front and rear hoops connected by tubing on sides or side hoops in a manner deemed acceptable by the inspector. Driver's head must not protrude above cage with helmet on while strapped in driver's seat.
    3. Roll cage must have a 3/16 “ inspection hole in non-critical area. Must have at least three (3) horizontal bars at driver's door welded to front and rear of roll cage members.

    WEIGHT

    1. Spec. Engine: Minimum weight for spec engine using a clutch is 2500 lbs after race.
      a. Minimum weight for spec engine using a power glide is 2525 lbs after race. 25 lbs must be added in front of mid plate when using a power glide.
      b. Minimum weight for spec engine using aftermarket transmission is 2550 lbs after race. 50 lbs must be added in front of mid plate when using aftermarket transmission.
    2. Crate Engine: Minimum weight for crate engine using a clutch is 2400 lbs after race.
      a. Minimum weight for crate engine using a power glide is 2425 lbs after race. 25 lbs must be added in front of mid plate when using a power glide.
      b. Minimum weight for crate engine using aftermarket transmission is 2450 lbs after race. 50 lbs must be added in front of mid plate when using aftermarket transmission.
    3. All lead must be securely mounted with 2 ½” bolts.  Lead must be painted white & have your car number on it.

          WHEELS

          1. Ten (10) inch wheels are legal until June 30th, 2013.
          2. Wheel width must not exceed eight (8) inches. No aluminum wheels. Bead locks allowed on right rear only.
          3. Wheel discs (Mud Plugs) allowed but must be bolted or welded or foam type. No ZUS fasteners.

                TIRES

                1. Ten (10) inch tires (asphalt take-offs – no new tires) are legal until June 30th, 2013.
                2. American Racer G-60 (KK704) modified tires. Maximum tire width of nine (9) inches mounted on a conventional one-piece steel wheel with a maximum width of eight (8) inches.
                3. Tires maybe re-grooved.

                      DIFFERENTIAL/REAR END

                      1. Any passenger car type or truck rear end may be used.
                      2. No aluminum. Full spools permitted. No quick-change devices allowed.
                      3. Floater rear ends are allowed.
                      4. 16” is the minimum length rear trailing arms can measure from center to center. 1” tolerance from side to side.

                              BRAKES

                              1. Disc or drum brakes may be used front and rear.
                              2. No aluminum disc or brake calipers allowed.
                              3. Brakes must be operational on all four (4) wheels and must lock up all four wheels during inspection.

                                    FUEL SYSTEMS

                                    1. Gasoline only. No oxygen bearing additives. No pressurized fuel systems.
                                    2. Fuel cells mandatory. Fuel cells must be encased in an approved metal container of no less than 20-gauge steel or 1/8 inch aluminum. Fuel cells must be mounted between frame rails as far forward as possible and using four, two (2) inch by 1/8 inch metal straps, two in each direction.
                                    3. Bumper must be equipped with a drag loop extending below bottom of the cell.
                                    4. Fuel cells must not extend below the rear end housing.
                                    5. 32 gal. maximum.
                                    6. No electric fuel pumps.

                                                BUMPERS

                                                1. Bumpers must be used front and rear.
                                                  a. Front bumper must be mounted on frame end and be of a semicircle configuration with the bottom loop parallel to the ground. Front bumper must be ten (10) inches high from bottom bar to top of top bar. Material must be one and one-quarter inch minimum, two-inch maximum O.D. steel pipe.
                                                  b. Rear bumpers may be constructed of pipe, square tubing, but must not have sharp edges. Rear bumpers and nerf bars must not extend beyond width of rear tire.
                                                2. Bumpers must be able to support car when lifted by wrecker.

                                                    SEAT AND SEAT BELTS

                                                    1. Racing seat mandatory.
                                                    2. All cars must be equipped with an approved quick release type seat belt and shoulder harness securely fastened to frame and roll cage. Seat belt material should be at least three (3) inches wide AND CANNOT BE OLDER THAN 2 YEARS.
                                                    3. Seat and steering wheel may be located to suit driver's taste, but must be kept on left side of car.
                                                    4. No center steer.

                                                            ENGINE OPTIONS

                                                            1. CRATE ENGINE: Unaltered sealed GM crate engine #88958602.  Any different, altered, or missing GM seal bolts will result in disqualification, loss of all track points for the season, and a one year suspension.
                                                            2. SPEC. ENGINE: Must use OEM cast iron, American make V-8 engines only. 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.  Maximum cubic inch limits: GM 361 c.i., Ford 360 c.i., Chrysler 370 c.i., no tolerance. No 400 or larger cubic inch parts allowed.  No aluminum valve train parts allowed.  Engine must appear stock.  Only stock appearing crank and rods allowed. No H Beam Rods. No knifing or profiling of crankshafts. No lightening of any kind to crankshaft. No aluminum / lightened or light weight engine parts allowed.  A minimum 1-inch plug above the oil level in the side of the oil pan mandatory.  If you do not have an inspection plug the oil pan will have to be removed at time of inspection. Plug must be put in a manner where crank shaft & rods can be seen for proper tech inspection by official or pan will have to be removed for inspection.
                                                            3. GENERAL MOTORS: Must be 3.48-inch stroke and 4.060-inch maximum bore.
                                                            4. COMPONENT GUIDELINES: Must use one of following blocks: 3892657, 3914678, 3932388, 3932386, 3956618, 3970000, 3970006, 3970010, 3970014, 10066033, 10066036, 14010207, 14010209, 14010287, 14016376, 14016379.

                                                            ENGINE LOCATION

                                                            1. Rear of engine (bell housing flange) must be at least 72 inches forward from the centerline of the rear axle.
                                                            2. The center of the crankshaft must be within two and one-half (2 1/2) inches of centerline of the ball joints.

                                                            GENERAL MOTORS

                                                            1. May use any stock or after-market stock replacement head. Vortec head is OK. No angle milling allowed. Porting or polishing is not allowed. Maximum 2.02” intake valves and 1.60” exhaust valves. 3/8” or 7/16” studs may be pinned or use screw in type with 11/32” valve stem minimum. Aluminum rocker arms allowed. Poly locks allowed. Stud bindles are allowed. No gasket matching allowed. Flat top or dished pistons only. Must use flat tappet cam and lifters. No mushroom lifters. Cannot alter lift bores. May use oil restrictors. Valve spring size 1.437” and no larger. Any length push rods allowed. 10.5 to 1 compression maximum. 185 maximum cranking compression.

                                                            FORD

                                                            1. Stock cast iron blocks 260, 289, 302 or 351. Maximum 360 cubic inches. Any Ford cast iron OEM production cylinder head with in line valves (no canted valves) and with valves no larger than 2.02 inch intake 1.60 inch exhaust maximum. Head number: Ford World Products 53040, e351, Dart 13311112, RHS 35302.  No SVO heads or blocks. Flat top or dished pistons only. No porting, polishing, or alterations to heads of any kind. Flat milling allowed. Guide plates, screw in studs (0.375 inch max.) Poly locks allowed. No stud girdles. Stamped steel, OEM style, or stamped steel roller tip stud mounted (0.375 inch max.) Rocker arms only. Any length push rods allowed. OEM diameter springs must match heads.

                                                            CHRYSLER/DODGE

                                                            1. Stock cast iron blocks 318, 340 or 360. Maximum 370 cubic inches. Flat top or dished pistons only. Head number: RHS 20300, 20301. Any OEM factory production Chrysler heads allowed with inline valves (no canted valves) no larger than 2.04 inch intake and 1.70 inch exhaust. No porting, polishing, or alterations to heads of any kind. Flat milling allowed. No W-2 or aftermarket heads allowed. Chrysler may use OEM aluminum rocker arm bars. OEM diameter springs must match heads. Any length push rods allowed.

                                                            TRACK HAS OPTION TO ENFORCE THESE RESTRICTIONS WITH A CUBIC INCH PUMP GAUGE OR BY VISIBLY CHECKING PARTS AND PART NUMBERS. DISQUALIFICATION AND LOSS OF POINTS IF FOUND ILLEGAL.

                                                            SHOCKS

                                                            1. One steel, nonadjustable, unaltered shock per wheel only. All shock mounts, including screw jack type, must be welded. No external or internal bumpers or stops.
                                                            2. No coil over, air, or remote reservoir shocks. No Schrader valves or bladder type valve allowed.
                                                            3. Front half of any shock may be shielded.
                                                            4. One or all shocks may be claimed per event for $75 each.

                                                            FRONT SUSPENSION

                                                            1. Front suspension must match frame and be in stock location. Parts must be replaceable from stock OEM type parts from same type suspension except upper A-frame and A-frame mount.
                                                            2. Tube type upper A-frame may be used. Fabricated A-frame mount may be used but must be in stock location.
                                                            3. Lower aftermarket A-frame can be used but must be in stock location.
                                                            4. No fabricated spindles.
                                                            5. Adjustable strut bars can be used on front end only.
                                                            6. No coil over shocks allowed either front or rear.
                                                            7. One shock per wheel.
                                                            8. Steering box must be stock OEM type and be in stock location. No rack and pinion steering. No center steering.
                                                            9. Adjustable sway bars allowed.

                                                            REAR SUSPENSION

                                                            1. TWO OPTIONS: Aftermarket three link design or multi-leaf spring design. All components must be steel. All mounts and brackets must be welded or bolted solid. You may not run a dampening shock above the rear end. No limiting device, chains, tethers, straps of any kind will be permitted on front or rear suspension.
                                                            2. THREE LINK DESIGN REQUIREMENTS: Must use minimum 16 inch center to center of heims. Lower trailing arms both sides needs to be the same, (1/2 “ tolerance ). No swing arms. Solid pull bars are required, no spring bars, rubber bushings or any type of torque devise. Pull bar must be mounted solid (no rubber or any type of cushion in the mounting bracket) must be located at top center of rear end housing and remain centered on housing over drive shaft (1inch tolerance left to right). May use minimum 23 inch long pan hard bar located behind rear end housing or minimum 19 inch long J-bar mounted to a steel pinion bracket.  Measurements are from center of heim joint to center of heim joint. May mount rear spring directly over axle housing or use coil over eliminators (sliders). Lower spring perch or coil cover mount must be welded to rear end housing. No birdcages or floating mounts allowed. Must use steel upper weight jack if springs are mounted over axle housing. No shock type eliminators.
                                                            3. MULTI-LEAF SPRING DESIGN REQUIREMENTS: Leaf spring must use steel multi-leaf springs with no additional suspension components besides one shock per wheel. Adjustable aluminum lowering blocks allowed. No coil springs can be used with leaf springs. No altering of leafs of any kind, no taping, no cutting, no greasing. Must run the same rate of leaf spring on both sides.                         

                                                            REAR END

                                                            1. Any steel approved OEM passenger car or truck non-cambered rear end allowed, must be centered in chassis.
                                                            2. All components must be steel, except lowering blocks, axle cap, and drive flange. Safety hubs (floater) allowed.
                                                            3. No quick-change devices. Inspection hole in housing required. Mini-spools only. Ring gear, center section and yoke cannot be lightened.
                                                            4. Solid steel axles and one piece drive flanges only.
                                                            5. 16” is the minimum length rear trailing arms can measure from center to center. 1” tolerance from side to side.

                                                            CARBURETOR

                                                            1. CRATE MOTOR: May use any Holley 4 barrel carburetor, all components (float bowls and main body) must be Holley manufactured. Metering blocks and base plate may be billet aluminum non-Holley. No aerosol-style carburetors allowed. May use one inch thick carburetor spacer, must use Moroso part #64940 or a 2" open plastic spacer allowed with GM crate. Maximum 0.100 inch thick carburetor gaskets only.
                                                            2. SPEC. MOTOR: Must use stock Holley 4412 500 CFM carburetor only. No Modifications. No adjustable metering blocks. Choke horn must be intact. May remove choke butterfly. Must use Edelbrock Performer  4 bbl. intake manifold.  GM 2101,2116 when using vortex heads Ford 2121, Chrysler 2176 ONLY.  No Performer RPM or air gap manifolds.  Must use Mr. Gasket part No. 1933, Moroso part. No. 64966, Speedway part no. 910-11510, or HVH part. No. 4412-2 carburetor adaptor. Carburetor claim $175 & trade. Top 4 cars are subject to carburetor claim. Claim must be made within 5 minutes after checkered flag drops & car claiming carburetor must be on lead lap. Refusal of claim results in loss of pay & points for night & 2 week suspension.

                                                            OIL PANS

                                                            1. Extra capacity oil pans are permitted. No dry sumps allowed.
                                                            2. Oil pump must mount in stock position.

                                                            STARTER

                                                            1. Engine must have working starter and must be capable of starting car on demand.

                                                            TRANSMISSION/DRIVE SHAFT

                                                            1. All forward and reverse gears must be operational, plus a neutral position. With engine running and car in still position, driver must be able to engage car in gear and move forward, then backward. No ‘in and out’ boxes or quick-change devices allowed.
                                                            2. Functioning shift levers must be in OEM location.
                                                            3. One steel or aluminum OEM style/size flywheel or steel OEM style/size flex plate allowed, must be bolted directly to end of crankshaft.
                                                            4. Automatic: Must be unaltered, two or three speed, OEM production case with a functioning stock appearing pump. Must have an approved scatter shield constructed of .125-inch by three-inch steel, 270 degrees around top of flex plate.  Splined drive flange coupler with internal pressure relief device, gate valve, or torque converter (10-inch min) only. Hydraulic lines may not extend in to cockpit.
                                                            5. Manual: Must be unaltered, two, three or four speed in OEM production case. No five (or more) speeds allowed.  Must have working clutch inside explosion-proof steel bell housing with one hole for throw out bearing lever or hose, must be 270 degrees around top of clutch and flywheel area.  MINI-CLUTCH ALLOWED.  Components must rotate, consistent with engine RPM, while car is in any gear.
                                                            6. OPTION:  May use aftermarket transmission - Bert, Brinn or Falcon. Refer to weight rule section.

                                                            DRIVE SHAFT

                                                            1. Minimum two-inch diameter, white, steel drive shaft. Steel slip-yokes only.
                                                            2. 360-degree drive shaft loop required and must be constructed of at least .25-inch by two-inch steel, or one-inch tubing, mounted six inches back from front U-joint.

                                                            BATTERY

                                                            1. All batteries must be mounted in a safe manner.

                                                            HELMETS & FIRE SUITS

                                                            1. Helmets are required and must be worn at all times car is on the track.
                                                            2. All drivers must wear fire suits of a flame-retardant nature. Two-piece suits are allowed.
                                                            3. Fire resistant gloves are mandatory. Fire resistant boots are highly recommended.

                                                            EXHAUST

                                                            1. Round tube headers only. All primary header tubes must enter directly into one collector, at same point at the end of header. No extensions on header. Turn down allowed. No stepped header allowed.
                                                            2. No exhaust sensors, cross-overs, extensions, merge collectors, inserts or balance tubes. No Tri-Y Headers.
                                                            3. Exhaust must be directed away from areas of possible fuel spillage. No zoomies. No 180 degree headers.

                                                            GAUGES/ELECTRONICS

                                                            1. 12-volt ignition system only. HEI distributor only. OEM firing order cannot be changed. Ignition rotor, cap, coil and module must remain OEM appearing.
                                                            2. No ignition boxes, remote coil or accessories when using the 360 HP spec engine. All cars must use part # MSD 8728 Soft Touch Rev Control box. Must be mounted out of reach of driver.
                                                              a. 602 CRATE: mandatory 6200 RPM chip.
                                                              b. SPEC ENGINE: mandatory 7000 RPM chip.
                                                            3. All wiring must be visible for inspection.
                                                            4. Only gauges allowed are analog oil pressure and water temperature and analog tachometer (memory recall allowed). No electronic traction control allowed.
                                                               

                                                            ALL RULES (OR INTERPRETATION THEREOF) WILL BE DETERMINED BY TRACK OFFICIALS. ALL TRACK OFFICIALS WILL HAVE THE RIGHT TO CHECK YOUR CAR AT ANYTIME, FOR ANY REASON. ALL TRACK OFFICIALS’ DECISIONS ARE FINAL.
                                                             

                                                            IF IT DOESN’T SAY YOU CAN’T DO IT - IT DOESN’T MEAN YOU CAN DO IT!
                                                             

                                                            Competitive racing can result in injury and/or death to the participant.  No expressed or implied warranty of safety shall result from publication of, or compliance with these rules and/or regulations.  The rules and regulations are ONLY intended as guides for the conduct of the sport.  They are in no way a guarantee against injury or death to a participant, spectator, officials, or other.

                                                            © 2013 Tri-State Speedway

                                                            Click here to print your copy of these rules.