SHIPPENSBURG SPEEDWAY INC
2014 THUNDER CAR RULES
ANY FOUR CYLINDER PISTON TYPE ENGINE REAR WHEEL DRIVE CAR. NO CONVERTIBLES, FOUR WHEEL DRIVES,
OR JEEP TYPE VEHICLES. MAXIMUM STOCK WHEEL BASE 105”. MINIMUM WEIGHT 2,350 LBS WITH DRIVER.
ENGINE AND TRANSMISSION: The engine must be strictly stock for that make and model and in its original
mount, no motors mix/match. No stroked motors no turbos. Solid motor mount allowed in its original mount
position. Maximum .040 overbore. No Aluminum Heads except as it was built in the factory. Any factory or after
market headers allowed, muffler optional. Exhaust must extend outside the body past the drivers compartment,
with 2 ¼” inside diameter pipe exiting the car, if run through the drivers compartment it must be shielded.
Exhaust must exit to side of car – not to the ground. No dual overhead cam engines. After market 5.2 rods are
allowed. Maximum cam lift .480. Adjustable cam pulleys are permitted. Under drive pulleys are permitted to run
water pump. No shaving, porting, polished or deburred heads. Valve sizes must remain stock. Pistons must be
flat top type with stock profile and stock wrist pin height. No polishing or cutting and balancing or rotating
assembly. Stock 500 CFM Holley carburetor or factory stock or stock replacement. Carburetor spacers 1” max
allowed. No fuel injection of any kind including intake. Electric fuel pumps allowed. Electric fuel pumps must be
mounted under the hood or tank area and it must be connected to an oil pressure safety switch. Radiator and oil
coolers must be mounted in stock location.
ENGINE SPECS: FORD 2.3. CHEVY 2.5. CHRYSLER 2.6.
MIN HEAD CC
FORD:
GENERAL MOTORS:
MITSUBISHI:
2000CC 48.2
iron duke 151 48.82
2600cc 50.2
2300CC 54.8
baby duke 68.82
DRIVE TRAIN: Stock rear and housing. Rear may have spider gears welded. No Spools of any kind allowed. Stock
transmission and clutch. Stock Flywheel.with min. weight of 15 lbs. No aluminum, must have all forward and
reverse gears. Stock drive train only, no aluminum driveshaft’s, 2 driveline hoops are mandatory and must
encircle the drive shaft.
SUSPENSION: No modifying of the suspension other than stated. Suspension parts must remain absolutely stock
for that year, make, and model of car. Only rubber spacers allowed, No other spacers, lumber, or chains, etc.
may be used to alter suspension of the car. Racing springs will be permitted no screw adjustable springs allowed.
No steel plated to reinforce body or chassis. No cutting or moving of components. Shifting top of strut is allowed
as long as it stays within original strut tower. Cutting the strut tower for adjustment is allowed. no coilovers.
TIRES & WHEELS: All wheels must be reinforced to prevent their loss. Racing wheels allowed. No aluminum,
mag, diecast, trick wheels or bead lock allowed. Rim inset or rear spacing permitted. Maximum 8” width
allowed. 13” or 14” diameter steel wheel only. No screws allowed on outside. Bead-lock may be used on right
rear only. Tires must be stock passenger car tires only. No racing DOT, truck, studded, recap, racing, or trick gum
ball tires of any kind permitted. BF Goodrich legend tires are legal. Tire grooving is allowed. 60 or 70 series DOT
tries. Max. tire size is 205-70-14. Max. 8” tread width on tires with a ½” tolerance measured from edge of tire
tread.
BRAKES: Brakes must be in good working order at all times. Stock brake system must be used for make and
model of the car being used. May disconnect right front brake.
IGNITION: No after market components or MSD boxes.(except coil) Must have master disconnect switch clearly
marked on rear shelf, behind driver near battery.
ROLL CAGE & BRACING: Roll cage must be 1 ½ OD minimum tubing, minimum .095 wall tubing must be used.
Roll cage must be securely welded to the frame or plate welded to floorboards at rocker panel on 6” x 6” plate
minimum. Sub frame may be tied together. Roll cage must extend from windshield to rear of drivers
compartment with a loop at the front and rear. A 1” pipe must be welded to roll cage in center of windshield
opening. Door bars and bracing must be minimum of 1 ½” .095 tubing. Drivers area must have approved padding
on roll cage and door bars. Two bars may be added from dash area to front in line with frame but stop 6” from
rear of bumper and two bars from back of roll cage to rear of car not attached to bumper. (must be inside body)
no down bars. Racing seat is mandatory and must be securely attached to roll cage in stock location. Must be
high back seat or have head rest. Seat belt must be securely attached to roll cage, if bolted minimum 3/8”bolt
required. One non visible bar may be used to protect radiator, it must be mounted bumper and hood, not to
protrude past bumper, 1 ½” tubing max. No Sharp edges on bumpers at any time. Bumpers may not be reenforced from behind. Bumpers must be stock width and height and be mounted in stock location. Front and
rear bumpers must have a bar attached to the ends that goes back into the body or attached to the frame. No
trailer hitches may be on the car at any spot and can not protrude past outside edge of the tires. From the front
of the strut tower forward may be replaced with max 2x2 tubing. External rub rails allowed, must be tight to the
body. We highly recommend that you do not use filler of any kind in the body or frame of the car. May reinforce
lower radiator support with sheet metal.
FUEL CELL: Fuel cell mandatory. Must be securely mounted in trunk area. If plastic fuel cell is used, it must be
completely enclosed in metal. Steel fuel line or flex steel or blue racing fuel line may be run inside car, but must
be enclosed in rubber and sealed at both ends. Fuel line check valve is mandatory, shut off switch suggested.
INTERIORS: All interior glass and all flammable parts must be removed. The stock steel unaltered floor pan,
firewalls, trunk, trunk floor and all wheel wells must be retained. Trunk floor may be altered to accommodate
fuel cell. If interior is built up it must have an access panel installed. No mirrors allowed. All holes in driver
compartment must be filled in with metal. Windshields must have heavy screen. No windshields allowed, no
plexi glass anywhere on body. Lexan may be used for visors, maximum of 6”, and rear side windows only.
BODIES: Cars must remain strictly stock. Aftermarket nose and rear bumper covers are allowed. No
interchanging, no cutting, no chopping, channeling or shortening allowed, except chopping of interior door
panel for roll cage clearance. No holes in the hood. Trunk and hood lids may also be stripped. Hood must be
kept in place by secure quick release pins. Body sheet metal must be in place at start of race. All glass and lights
must be removed. All doors must be welded or bolted shut. No skirting, spoilers, or hood scoops of any kind
allowed. Stock sheet metal only. If rear bumper covers are used, a visible chain or cable must be securely
fastened to bumper for easy wrecker hook up.
MISCELLANEOUS: Battery may be moved inside of car, but must be covered and securely fasted with a metal
hold down over the battery. All weights must be securely bolted with lock nuts, double nuts or nuts with cotter
keys. Weights must be painted white and have car number painted on them. Any loss of a wheel requires that
you leave the track. Rupture of a gas tank receives a black flag. Car must be painted in a respectable manner. Car
numbers must be at least 18” high on both sides of the car and on the roof. A plate with a min. 6” number will
be required on the right hand corner of front headlight. FUEL: No alcohol allowed! Racing fuel is allowed. Fuel
testing may be done at the discretion of the track tech director. During tech only tech official and 2 car
representatives are present.
Tech will be the top four drivers in points and the race director. Race director has final say.
ANYTHING NOT COVERED IN THESE SPECIFICATIONS WILL BE TO THE DISCRETION OF
THE TRACK TECHNICAL PERSONNEL WITHOUT RECOURSE FROM ANY DRIVER OR
OWNER. ALL SEPCIFICATIONS ARE SUBJECT TO REVISION