2008 Hobby Stock Rules
Revision 1 September 2007
November 18 - 2007
IMCA Legal Hobby Stocks are also considered legal & are permitted to compete.


AMENDMENTS TO THE RULES FOR 2008 HAVE BEEN UNDERLINED

ROLL CAGE -
Must use .095 -inch tubing, at least 1.75-inch diameter for main cage and door bars. No offset cages. Four-post roll cage must be used, front and rear hoop welded to the OEM frame. Rear hoop must have "X" brace, consisting of one horizontal and one diagonal bar, 1.25-inch O.D. and .083-inch wall thickness. Front down-bars must be tied together. Must be minimum of 40 inches between front and rear down bars at top of door panel. No more than 41 inches from top center of windshield to front edge of rear hoop; no more than 13 inches to front edge of front hoop and top halo must be no less than 40 inches across, outside to outside. Must have minimum of one cross bar in top of halo. Required rear kickers and engine hoop must be minimum 1.25-inch tubing, with .083-inch wall thickness. Three horizontal door bars on both sides are mandatory. Minimum of four uprights tied from frame to top door bar on driver side, three on passenger side. May have two bars for protection in front of radiator, behind bumper, within confines of body, no wider than stock frame horns. May tie front horns together. All bars, front and rear, must be inside body. Steel doorplates, 18-gauge or .049-inch minimum thickness metal, must be securely welded to outside of door bars on driver's side. Plate must cover the area from the top door bar to the rocker panel and from the rear down post to five inches in front of the seat. Must be visible for inspection. Absolutely no square tubing or galvanized pipe allowed. Fuel cell protection bar may be used, mounted frame rail to frame rail, no higher than the fuel cell and inside the trunk area. Maximum 1.75-inch pipe.
SAFETY-
Five point safety belts, sub belt and shoulder harness required. No Y type shoulder harness allowed. Belts must be mounted to cage. SFI approved full fire suit, fire retardant neck brace and fire retardant gloves required, racing shoes recommended. Hans or Hutchins device allowed with out neck brace. Helmets are required and must be Snell SA90, SA95 or SA2000. Helmet must be worn at all times car is on the track and must accompany vehicle at time of inspection. Roll bar padding is required in driver compartment. Fire retardant padding recommended. Full size (minimum 16-inch x 20-inch) window net required (no string-type nets). Window net to be mounted so latch is at top front of driver side window. Kill switch required within easy reach of driver and must be clearly marked "OFF" and "ON". 360-degree drive shaft loop is required and must be constructed of at least quarter-inch by two-inch steel, or one-inch tubing, and should be mounted six inches back from front U-joint. All cars must have a high-back aluminum-racing seat fastened to roll cage with minimum 3/8 inch bolts, Driver's shoulders can be no further back than the front of the window post ('B' pillar).
ELECTRONICS -
 No transmitting or listening devices allowed in car. No electronic monitoring computer devices capable of storing or transmitting information except tach allowed on cars. No digital gauges allowed on car. No ignition control boxes allowed, OEM ignition only. No electronic traction control devices allowed. No alternators allowed.
FUEL -
 Pump Gas or 10% Ethanol blend fuel only. Racing fuel cell required no boat or stock automotive fuel tanks. Must be securely fastened, (above level of stock trunk floor), by at least two 1/8-inch thick by 2"wide solid steel straps, around entire cell. Metal firewall must be between driver and fuel cell. All cell mounts must be steel, attached to frame/cage. No adjustable fuel cell mounts. Fuel cell must be in a steel container Max 18 gauge. Fuel cell vents, including cap vent, must have check valves. Fuel lines through driver compartment must run through metal pipe or metal conduit. No fuel filters in driver's compartment. No fuel pressure regulators or fuel return lines on the car. Stock appearing fuel pump only. May run factory fuel pump with factory return line at the pump.
BATTERY -
 One 12-volt battery only must be in a marine-type case securely mounted to frame or roll cage in a metal frame behind the seat or in trunk area. Max 18 gauge Battery Box.
TIRES & WHEELS -
 Stock (OE) 205/75, or 205/70, 14-inch, or 15-inch passenger tires only. All four tires and wheels on car must be same size. Tires must be inside body.
No mud, racing or fancy, exotic, trick gumball tires allowed. No softening, conditioning, sipping or grooving allowed.
Must be D.O.T. stamped wheels with standard bead bump - must weigh a minimum of 21 pounds.
No racing wheels or mag wheels allowed. Spoke steel wheels allowed. Maximum seven-inch wide steel wheel. Reinforcing of stock wheels recommended. One inch steel lug nuts required. No wheel spacers allowed.
Vehicle Weight-
As we have no weight limit for the cars that race at our speedway it shall be a judgment call on behalf of the tech officials if you have over done areas of you car in order to gain rear percentage. IE solid bar tubing in rear of car, heavy material bumper braces, heavier than needed replacement rear frame rails, etc.  If we deem necessary we will require you to add weight in the engine compartment to offset the conditions found. All replacement frame tubing will have 1/2'" holes drilled every 6"for inspection purposes.
FRAME -
Frame must match body. 109-inch wheelbase minimum for unibody cars, 107.5-inch minimum for full frame cars - no more than one inch difference from side to side.
Frames may be "X" braced. Rear of frame behind rear tires, from a point no further forward than one inch behind the factory seam, may be replaced in stock location with two-inch by three-inch steel tubing with .095-inch wall thickness. All replaced rails must have inspection holes in the tubing.
Factory seam must remain visible. Must replace the same length material removed.
Unibodies must be tied - rear frame to front frame. No station wagons, convertibles, front-wheel drive, four-wheel drive or rear engines. Bumpers must be in stock location.
Front and rear bumpers must be capped to fender the width of the bumper. No reinforcement of bumpers. Bumper may use 1 3/4" x .095 wall round or square tubing to mount bumper to car. 
This along with good fender caps and safety cables will keep bumper on the car with out adding extra weight.
All Bumpers must run 2 safety cables from bumper to frame. Bumper caps must be made of 18 gauge metal with 1/4 inch bolts, (No Rivets.) Inner bumper brace must have inspection holes drilled in them.
SUSPENSION & STEERING -
Must be original type suspension and steering and match the frame. No rear independent suspension allowed. Steel springs only. No add-on quick steer boxes. No remote reservoirs on power steering pumps. All shocks must be steel non adjustable with OEM mounts.  All shocks must mount in the stock location (top and Bottom). Driver cannot claim shocks and engine in the same event. No spacers, lumber, chains or cables allowed.
BRAKES -
Master cylinder must be in stock location. Approved OEM brakes on all four wheels must work. No OEM Antilock Brake Systems. No rear wheel disc brakes. All drums and rotors may not be machined or worn past the factory minimum thickness or maximum diameter. No after market brake pedal assemblies allowed. No brake shut-off or bias allowed. No Brake pressure valves of any kind on the car.
BODY -
1960 or newer American made stock passenger automobile with factory steel top. No Camaros, Firebirds or Mustangs. Sunroofs and T-tops must be reinforced and enclosed. All bodies must be approved OEM (and be mounted as factory) IE Doors must meet the rocker panels Roof must have factory rack.  After market plastic nosepieces allowed. No aftermarket tailpieces, spoilers, wings, skirts (If skirts are necessary than no lower than stock frame rails), air scoops or anything that alters the stock appearance. No aluminum hoods. Hood must be separate from fenders - no one-piece or tilt front ends. No gutting of hoods or trunks. No cutting out kick panels. All hoods and trunks must be securely fastened and the back of hood must be sealed off from driver's compartment with metal. Steel rub rails no bigger than one inch by two inches may be attached to body from fender well to fender well, flush with body May also use the Lexan rub rails. Maximum seven-inch metal sun visor (measured anywhere) may be added to top of windshield opening only.  All sharp edges, torn fenders and body panels to be repaired prior to next race.  Must have a minimum of three windshield bars in front of driver. No ballast allowed. All glass, plastic, upholstery, rear seat, lights, mirrors, and chrome removed. Dash is not to extend more than 24 inches back from center of lower windshield opening. Dash must be flat except for cowl in front of driver. No other interior tin or covers. All doors must be secured shut (welded, chained, bolted, no rivets) the front inner wheel wells may be removed, but not the rear wheel wells.  Must have bumper caps as wide as bumper and must be bolted or welded to body and bumper, minimum 18-gauge metal, aluminum or steel, no sharp edges. All window openings to remain open. If you have a home made nosepiece it must go straight up and down and must be bolted behind bumper.
DRIVE TRAIN -
Unaltered OEM, Manual Transmission, with all forward and reverse gears operational. (I.E. 4 speed transmissions must have 4 forward and 1 reverse gears). Or an OEM automatic transmission, with original bell housing and functional torque converter containing a minimum of three quarts of fluid, or approved OEM (10.5" or larger) single organic disc-type clutch, solid center organic clutch disc OK  inside an explosion-proof steel bell housing on manual transmission only. No button clutches.
All bell housings must have a 2 x 3 inch removable inspection hole directly below the clutch and flywheel for inspection purposes or bell housing may need to be removed for inspection. No aluminum or lightened flywheels. Manual transmission Flywheels must weigh at least 16 lbs. Automatic must have an approved scatter shield (may be constructed of quarter-inch by three-inch steel, 270 degrees around flex plate or flywheel. Torque converter must have a minimum 1/8-inch plug. No truck rear ends allowed. Steel axles only. Nine-inch Ford rear end allowed, but must be mounted like stock rear end for that make and model. Minimum 2.5-inch diameter steel drive shaft must be painted white. Drive shaft centered in car tunnel. Rear end may be welded or mini spool, no full spools. No Light Weight Ring Gears. No floater rear ends. Rear suspension must match frame. No electronic or mechanical traction control devices allowed
NUMBERS -
All cars must be numbered with large, legible numbers on sides, top and rear panel. Numbers must be in contrasting color from body, in all light conditions. Numbers on side of car to be at least 4 inches thick and 20 inches high.
 Numbers on top must be at least 4 inches thick and 30 inches high.
 ENGINE, CARBURETOR & IGNITION
A. Engine Block- OEM cast iron only, all modifications to factory service specs only. OEM bore and stroke combinations only, Lifter bores may not be altered.  Maximum 361ci (GM), 363ci (Ford), 368ci (Chrysler). Due to the many possible combinations of bore and stroke you may be asked to remove a head at the track for measurement. Gaskets will be at your expense. Subject to fine and loss of track points if found illegal.
B. Crankshaft- Must have a stock appearing rear crank flange. Balancing OK, No lightening, knife edging or reducing of the crankshaft circumference. It is recommended that you have a (2") inspection hole above oil level in Oil Pan or you will have to drop Pan for inspection. Ford and Chrysler will require pan removal to verify crankshaft
C. Harmonic Balancer- Must be of OEM design with rubber mounted dampener ring
D. Connecting Rods- Must be of OEM design (IE If stock rod was "I-beam than Aftermarket must be "I-beam) It is also required the aftermarket rods weight the same or more than OEM. Rod length is up to engine builder (does not have to be OEM length). Rods may use bolt and nut or cap screws to secure the caps.
E. Pistons- Cast or Forged, Flat top or Dished. No domed or gas ported pistons Allowed.
F. Camshaft- Solid Lifter or Hydraulic only, No Roller Camshafts allowed. Valley tray OK (recommend cutting tray at rear most lifter so lifter may be removed for inspection from the distributor hole).
G. Cylinder heads- must be unaltered approved OEM. All heads must have been used in a production vehicle. No limited production or special purpose over the counter only heads allowed. No porting, polishing or unapproved valve bowl work or other alterations of any kind to heads or intake. Heads may be reworked to accommodate the largest OEM valve size available in a production "on highway" use vehicle. If cutting new valve seats the ring left below the seat maybe removed with a carbide cutter in a head service machine only, one cutter angle only no multiple cuts. (No die grinder work anywhere no exceptions). Cylinder heads may use screw in studs and must have stock diameter single valve springs. No Bee hive valve springs allowed.
H. Valve Train- No full roller or roller tip rocker arms. No guide plates allowed. No stud girdles. Oil Deflectors allowed two bolts maximum.
I. Exhaust Manifolds- OEM cast iron exhaust manifolds only. No center dump or tubular steel manifolds allowed. Exhaust pipes must extend past firewall. Must remain dual exhaust, no crossover or ‘Y’ pipes allowed. No oxygen sensors allowed.
J. Intake Manifold- OEM cast iron two-barrel intake only. No aluminum intakes allowed.
K. Carburetor- All cars must run a stock two-barrel carburetor, no Holley. (GM venture 1.375", base 1.690", aluminum booster .250"). May remove choke, but no other alterations allowed. Conventional air cleaner housings only. No top flow air cleaner housings, cold air boxes or air cleaner ductwork allowed. No Carb spacers allowed. Hot air deflectors may be up and down between radiator and engine.
L. Fuel Pump- OEM style diaphragm pumps only. No fuel pressure regulators or electric pumps allowed.
M. Ignition System- OEM Stock appearing (all components) Distributors only. Must run stock firing order.
N. Cooling system-Minimum two-core approved steel or aluminum radiator. OEM steel or aluminum water pumps only. Steel or aluminum pulleys allowed. No serpentine belts allowed. Any overflow tubes are to be directed to the ground, between frame rails.
O. Starter-OEM starter must bolt in stock location.
P. Accessories- Stock steel accessory brackets only.  OEM accessories and brackets only. Accumulators and Accusumps must be mounted under the hood.

ENGINES ARE RESTRICTED TO NINE TO ONE COMPRESSION IN ONE OF THE TWO FOLLOWING METHODS-9.0 to 1 compression ratio using Whistler. (Blue Box)
(or)
Cast iron heads only. OEM Production heads only. Flat top pistons only; GM cars - approved steel head numbers are - 014, 195, 267, 330, 336, 339, 388, 393, 441, 445, 454, 487, 493, 545, 598, 624, 642, 709, 799, 813, 862, 881, 882, 920, 991, 993, 997; Ford cars, no after market or SVO heads; Chrysler cars, no after market or W2 heads, 360 cubic inch heads only. Must be 76 cc heads or larger. Other heads may be approved call FIRST!!

TECH QUESTIONS - E-MAIL TIM WEILAND

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