LIMITED MODIFIED (B MOD) CLASS
• ROLL CAGE: Must consist of continuous hoops, minimum 1.50‐inch O.D. tubing, with a minimum wall thickness of .095‐inch for main cage, frame mounted in at least six places, low carbon or mild steel recommended. Must consist of a configuration of front, rear and top hoops connected by tubing on sides or side hoops. 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. Foot protection bar required. Main cage no further forward than the rear of the engine. All bars forward of cage must be lower than hood.
• DOOR BARS: All driver’s side door bars and uprights must be minimum 1.5inch O.D. and .083‐inch wall thickness. Minimum three driver side door bars, parallel to ground and perpendicular to driver, and welded to front and rear of roll cage, passenger side must have at least one cross door bar, horizontal or angled, minimum 1.25‐inch O.D. & .083 inch wall thickness, and one top door bar, minimum 1.5 inch O.D. & .083 inch wall thickness, steel door plate 18 gauge or .049‐inch minimum thickness, must be securely welded to outside of driver side door bars and cover area from top door bar to bottom door bar and from rear hoop down post to 5 inches in front of seat. MUST BE VISABLE FOR INSPECTION.
• SAFETY: Rules apply at all times while car is on track. Snell rated SA95 or SA2000 helmet are required. SFI approved full fire suit, gloves and shoes required. Fire retardant head sock and underwear, head and neck restraints are recommended. Driver side window net or arm restraints required, and must be mounted so latch is at top front of window or arm restraints. Minimum three ‐ inch wide five ‐ point safety belt assembly required. Must be mounted securely to roll cage, recommended to be no more than three year old. Kill switch required within easy reach of driver and must be clearly marked ‘OFF’ and ‘ON’. A small Fire extinguisher in driver’s compartment is mandatory.
• FRAME: OEM complete 1964 or newer, perimeter American rear‐wheel drive passenger car frame only. No sports car frames. Frames must be full & complete, cannot be widened or narrowed, and must be able to support roll cage on both sides, except weight jack in original center line of spring tower allowed: frame may be cut a maximum 36 inches forward from center of rear housing: horns may be removed in front of steering box: front cross member may be notched and boxed for radiator and/or steering clearance:. Maximum seven inch wide opening in side of spring tower for spring removal. Maximum two inch wide by four inch tall frame stiffener may be welded directly to outside of left side frame rail. Minimum wheelbase is 108 inches, maximum is 112 inches, both sides. Maximum overall width (front or rear) shall not exceed 78 inches from outside of tire. No part of frame can be lower than four inches from ground except front cross member.
• BODY: Must be same width, front to rear, and parallel to OEM frames. Engine compartment must remain open (no side panels). Hood must be enclosed at rear, no panel in front of right door to engine compartment. No inner panels, No car covers. Must have front windshield and rear window support posts. Driver and passenger side windows must have at least 12inch opening, measured at center of window, between lowest point at top of window, whether roof or roll cage, and highest point at bottom of window, whether interior or body. May use Lexan in sail panels, may use full windshield. Must be fiberglass or aluminum full size roof rounded in all directions. (roof escape panel is allowed) plastic skirting allowed on bottom of doors and quarters. Outside of tires must be widest part of car. 5” spoilers allowed. Spoiler supports no more than 5” tall in rear, 2” tall in front, and 12” long.
• DRIVER COMPARTMENT: Must have a minimum three windshield bars in front of driver. Lexan or aluminum cowl panel in front of driver can be no wider than cockpit and no farther back than steering wheel. Minimum .125inch aluminum, or .060‐inch steel, complete floor pan required. Aluminum high‐back seat only and must be bolted in next to left side frame rail and ahead of rear tires. Bottom of seat can be no lower than bottom of frame rail. Driver must be sealed off from race track, driveline, engine, fuel cell, canisters and pumps. Accumulators cannot be mounted between driver and left‐side door bars. No devices that would enable driver adjustment to alter wheelbase or for weight jacking while car is in competition. No mirrors or reflective sun visors.
• FRONT SUSPENSION: All components must be steel, unaltered OEM, in OEM location and replaced by OEM parts, except tube type upper A‐frames with or without aluminum/steel cross shaft & mounts can be moved. OEM replacement lower A‐frames bushings only, no offset or bearing type. All lower A‐frame mounts and bolt holes on frame must be in stock location. Lower A frame must be right & left and of same design; rubber, nylon, or steel lower A frame bushings, no offset or bearing type: welded or bolted shock mount on lower A frame. Lower A frame mounts & bolt holes on frame must be in OEM, location. OEM ball joints only. Sway bar must be unaltered OEM. After market lower A‐Frames are legal.
• STEERING: All components must be steel, unaltered OEM, in OEM location. except outer tie rod end & adjustment sleeve may be replaced by a minimum .625‐inch steel rod end and steel tube; spindles can be ground for brake caliper clearance only; spindles must be right and left, and of the same design; bolt on spindle savers allowed; steel steering shafts and knuckles only. Steering quickener, steering wheel and quick release may be aluminum. Cockpit steering may be modified, must be kept on left side. No rack an pinion.
• SHOCKS: One steel non‐adjustable unaltered shock per wheel. One additional shock allowed on rear suspension. No bumpers or stops, no threaded body, front coil over, air or remote reservoir shocks. Front half may be shielded. No Schrader valves.
• SPRINGS: One steel, non progressive coil over spring and/or steel leaf spring per wheel only. One additional spring allowed on pull bar or li bar, may be progressive. Any coil spring must be at least 4.5 inches O.D. No torsion bars or air bags.
• REAR SUSPENSION: All components must be steel. No covers allowed. Any 3 link suspension allowed. Springs must be on the same side. All trailing arms/link bars must be steel tubing. Rear of frames may be altered to accept leaf or coil springs. Steel coil over eliminators or steel/aluminum coil over kits allowed. Must conform to shock and spring rule. One solid pull bar.
• REAR END: Any steel approved OEM passenger car or truck rear end allowed. Safety hubs (floater) allowed. All components must be steel, except lowering blocks, axle cap, and drive flange. Inspection hole in housing is required. Full steel spool, steel mini spool or welded rear ends only. Steel axles only. Quick change rear‐ends are allowed. No cambered rear ends. One piece drive flange only. No torque dividing differentials.
• BUMPERS AND RUB RAILS: Steel only. Bumpers must be used both front and rear at all times and welded or mounted with minimum .375‐inch bolts. Must be minimum 1.25‐inch O.D. tubing, .065 wall thickness on front, .095 wall thickness on rear. Two‐bar front bumpers must be mounted to frame‐end to frame‐end, no wider than width of material outside frame horns and with bottom loop parallel to ground. Top bar must be directly above bottom bar, minimum 6.5 inches apart, measured center to center. Rear bumper and nerf bars can be no wider than tires.
• TIRES AND WHEELS: HOOSIER A‐40S, M‐30S, G‐60, Americian racer g‐60 will be the only approved res. The Hoosier H40 and M60 is approved as a right rear op on. Grooving will NOT be permitted on the M‐30S, Sipping and grinding is allowed. Grooving, sipping and or grinding of the A‐40s, H‐40, M60, and g 60 res is allowed.
• No re‐caps. Aluminum or steel spacers only. May use approved bead lock, on right rear only. External, steel bead lock only and it cannot make wheel any narrower than 8 inches and no wider than 8.75 inches. Must use only steel bolts. Driver can run mud plugs on all 4 wheels. Rim‐mounted bleeder valves allowed.
• BRAKES: Must be steel approved OEM, operative four wheel, drum or disc. Must maintain OEM dimensions for Hubs/rotors and calipers, cannot be lightened. Bolt pattern may be changed. Larger studs allowed. Rear rotors may be aftermarket, min. 0.810‐inch thickness. Vented rotors only, no scalloped rotors. No brake shut‐off or pressure sensitive devices. One proportioning device allowed, front to rear only. Brake lines must be visible.
• EXHAUST: Round tube headers only. All primary header tubes must enter directly into one collector, at same point, at end of header. No exhaust sensors. MUFFLERS ARE MANDATORY 6” SLIP ON STYLE OR EQUIVILANT.
• FUEL SYSTEM: Mechanical fuel pump only and must be mounted at front of engine. Racing fuel cell required, maximum 32‐gallon capacity, must be in minimum 18‐gauge steel container. Cell must be securely mounted behind rear axle, between rear res, minimum of four inches ahead of bumper, minimum of ten inches above ground. Must mount with minimum two .125‐inch thick solid steel straps, two inches wide around entire cell. All cell mounts must be steel, securely welded to frame/cage. Protective tubing must cover rear and extend past both sides of cell. No part of cell shall be lower than protective tubing. Fuel cell vents, including cap vent, must have check valves. Pick‐up must be on top or right side of cell. Limit of one fuel filter. No cool cans. One naturally aspirated 2‐barrel 500 cfm 1 3/8” venturi carburetor only. May remove choke horn. No aerosol carbs. Allowed.
• FUEL: Must be Gasoline . NO performance‐enhancing additives. Upper cylinder lube allowed. Fuel sample may be taken from any car at any time. Penalty for illegal fuel is disqualification from event and $250 fine – first offense. No Alcohol. E‐85 allowed.
• WEIGHT: Minimum weight limit of 2,400 pounds if utilizing the GM 602 crate engine. Cars utilizing the open motor must weigh 2,600 pounds no tolerance, after race with driver in car. No weights and/or loose objects in driver compartment or outside body. Weights must be securely mounted to frame or roll cage and painted white with car number on it. Must be attached with at least two .5‐inch bolts. No titanium, magnesium. No gun-drilled, tubular, hollow bolts or studs.
• BATTERY AND STARTER: One 12‐volt battery only, must be shielded and securely mounted between frame rails. 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. Reverse‐mount starters with OEM case transmissions only.
• GAUGES AND ELECTRONICS: No transmitting or listening devices, timing retard controls, or digital gauges (including tach). No electronic monitoring computer devices capable of storing or transmitting information except along tach. No adjustable ignition control boxes. Only one 12‐volt ignition box allowed, must be out of driver’s reach. One high‐end rev‐limiter is mandatory. All engines must be chipped or programmed to the following maximum engine RPMs, GM 602 crate must run at 6,200 RPM, and open motors must run at7,200 RPM No electronic traction control devices ($10,000 fine).
• TRANSMISSION AND DRIVESHAFT: Must have at least two forward gears & one reverse, plus a neutral position. With engine running and car in still position, must be able to engage car in gear and move forward, then backward. Three speed, four speed and automatic. No five speed (or more) transmissions, in and out boxes, or quick change devices allowed. Functioning shift levers must be in OEM location on all OEM production type transmissions. Flex plates must be full steel, unaltered OEM or OEM replacement. Flywheel/ flex plate must bolt to engine between clutch assembly an crankshaft and all driving components within bell housing must rotate while car is in any gear. Transmissions must be one of the following designs:
MANUAL: Must have a standard OEM case & working disc‐type clutch
or approved cone or disc type coupler inside an explosion proof steel
bell housing. One fly wheel only, minimum 8.5 inches diameter. of clutch
disc must be a minimum of 5.5 inches. Clutch assembly must be steel,
except housing, which must be steel and/or aluminum. Bell housing can
have only a hole for throw out bearing lever or hose, must be 270 degrees around top
of clutch and flywheel area. Standard or reverse mount starter allowed, must
directly engage flywheel. No internal clutch type transmissions.
Except automatics. You may run Brinn, Bert or Falcon transmissions are allowed.
AUTOMATIC: Must remain in OEM or OEM replacement case with a
functioning OEM appearing pump. Must have an approved scatter
shield. Scatter shield must be constructed of minimum of .125‐inch by
three‐inch steel, 270 degrees around flex plate.
DRIVE SHAFT: Minimum two‐inch diameter steel drive shaft & must be
painted white. Steel slip‐yokes only. 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.
• ENGINE LOCATION: Rear of engine (bell housing flange) must be mounted at least 72 inches forward from the centerline of rear axle. Engines offset must be kept within 2 inches of centerline of front cross member with engine level. Minimum 11‐inch engine height from ground to center of crankshaft. Radiator must be mounted in front of engine. Cooling system may be modified. Overflow tubes must be directed to ground between frame rails.
• ENGINE SPECIFICAIONS: (OPEN MOTOR ) Any American made engine allowed. Steel heads, block & oil pan only. All engines must be able to be used in conventional passenger car without alterations. Engine mounts cannot be removed or altered. Castings and fittings must not be changed. Wet oiling system only. No Roller cams
• The Chevrolet Performance Parts 602 engine (GM Part Number – 88958602) will be an op on in 2018 (see G, below) All engines are to remain sealed from the factory. The original factory seals must remain unaltered, tampering, removal, modifications of any type and/or broken factory seals will not be permitted. (The Chevrolet Performance Parts 602 crate engine may have part number changes from time‐to‐time as issued by the manufacturer.)
B.) One (1) four (4) barrel 650 cfm unaltered Holley carburetor, Part Number
4777 or 80777 or Holley HP Carburetor Part Number 80541‐1, (‐2) will be
permitted. One (1) two (2) barrel unaltered 500 cfm Holley carburetor Part 4412 will be permitted. All carburetor components must remain unaltered. Any changes will result in disqualification from the event. Any alterations to the carburetor will not be permitted.
C.) All engines and all components must remain in their original configuration and form as purchased and/or delivered from the factory. Any changes will result in disqualification from the event. Any alterations to the engine will not be permitted.
D.) Any part that is sealed from the factory that has been tampered with and/or removed will result in an immediate penalty. The minimum penalty will be a $1,000 fine, loss of all accumulated points for the year and a loss of all earned purse money for the event night.
E.) Any issued penalty may include and will not be limited to a suspension of the car, driver, car owner, engine builder from participation in any Doe Run Raceway event.
F.) Any participant (driver, car owner and/or engine builder) that is found to have tampered with the engine will lose all points accumulated for the season, all earnings and the parts will be impounded for competitive analysis.
G.) Changes and/or alteration to the engine, intake manifold, cylinder heads, valve covers, valve components, front cover, oil pan, harmonic balancer and/or any parts on or in the engine will not be permitted.