2-1.1 Pro Stock Races

Oxford Pro Stock races are open to eligible models of American made passenger car production cars.

2-1.2 Approved Competition Models

The following cars are the eligible models approved for competition:

Chevrolet Monte Carlo

Pontiac Grand Prix

Ford Thunderbird, Taurus

Dodge Intrepid RT

All other makes and models must be approved by Oxford Plains Speedway.

2-2.1 Appearance

(a) Cars must be neat appearing and have complete bodies. Bodies may be aluminum, fiberglass, or steel. No carbon fiber panels permitted. Refer to OPS body measurement guide for actual body panel dimension requirements. Bodies must meet measurements provided by Five-Star stock car bodies and Oxford Plains Speedway.

(b) Full windshield must be used. Lexan type rear window and rear quarter panel windows may be used. Windshield must have three internal windshield braces spaced at least on five-inch centers and roughly centered upon windshield, constructed of minimum 1 (one) inch by 1/8" thick material. Rear window must be securely mounted with straps or edge clips made of metal, aluminum or steel and be internally braced so as not to distort under race conditions.

(c) A level plane across the rear deck lid must be maintained.

(d) A door "side window" is permitted. It must be mounted from the most front point of the opening to the 90 degree angle of the top of the windshield..

(e) No outside body bracing or rub rails permitted.

(f) Flat Rocker panels required. No bends or curves permitted.

(g) Only template bodies permitted.

(h) "Dirt type" front header panel not permitted.

(i) No cutting of front or rear bumper covers or fenders.

(j) C-Post must remain as manufactured.

The Five-Star Downforce body will be permitted as manufactured and shipped by Five-Star no alterations permitted. The body will be of fiberglass construction only. Doors may be aluminum. no carbon fiber permitted.

A "long" body template will be used to check Downforce body configuration.

NOTE: A list of defined measurements as to body width, rear deck configuration, rear window location, roof height, and other stock appearing body dimensions is available under separate cover. Non-conforming body dimensions may be assessed a minimum weight penalty of at least 75 pounds. A "long" body template will be used to check all body configuration.

2-2.2 Overall Car Weight

All weight will be with gas, oil, water, and driver and race ready. Minimum weight will be 2,825 pounds for maximum 10:5 to 1 compression ratio engine cars. Cars with an approved mounting of an A-B-C body will be 2,800 pounds. 

Cars running stock #2101 intake manifolds (not exceeding 12:1 compression) with stock 500 cfm carburetors and no dry sump engines may compete under the following weight rules: Perimeter chassis: Minimum weight 2,700 lbs and 58% left side weight. Straight rail chassis minimum weight 2,725 lbs and 58% left side weight.

Cars using open stock intake mainfolds with stock 500 cfm carburetors may compete under the following weight rules: Perimeter chassis, 2,700 lbs and 56% left side weight; Straight rail chassis, 2,725 lbs and 56% left side weight.

Cars running a Pro All Stars Series (PASS) GM #88958604 crate engine may compete under the following weight rules: Perimeter chassis, minimum weight 2,700 lbs and 58% left side weight; Straight rail chassis, minimum weight 2,725 lbs and 58% left side weight.

Maximum left side weight percentage on all cars must not be exceeded and must be maintained before, during and after each race. No refueling allowed. NOTE: Weight requirements may be adjusted by OPS in the interest of competition.

All car weights will conform to PASS specifications in 2006. For additional clarification, please consult Section 10.4 of the PASS rulebook.

2-2.3 Tread Width

Maximum absolute tread width is 66 inches

2-3.1 Spoilers

(a) Front Spoiler/Air Dam

Minimum ground clearance for front spoiler/air dam shall be 3 (three) inches with driver. Cars using an approved A-B-C body shall be 4 (four) inches with driver.

(b) Rear Spoiler

Rear Spoiler shall not exceed 5 (five) inches in overall or surface height. Cars with an approved A-B-C body will not exceed 6 1/2 inches. Spoiler SHALL not exceed 60 inches in width. Spoiler must be located at the rear of the trunk lid and be fastened on the rear side of the spoiler only.

NO side bracing or boxing permitted.

2-3.2 Seat

Driver’s seat must be specifically designed for auto racing and constructed of .125 inch thick aluminum. NO fiberglass seats permitted. Aircraft-quality hardware is required for attaching seat to seat sub-structure as described in diagram section.

2-3.2.1 Seat Location

Seat must be located in such a manner that the inside (left side) is a minimum of 8 (eight) inches distance from the nearest longitudinal door bar member.

2-3.3 Fire Walls

Interior of car must be completely enclosed in respect to engine compartment, track surface, tire wells, and rear fuel cell compartments. The area immediately beneath (floor) the driver and vertical panels surrounding the seat area (front and rear fire walls) and transmission tunnel MUST BE CONSTRUCTED of minimum 18 gauge steel (.047 inch) and be of welded construction. Other interior panels may be constructed of aluminum, minimum of .040 inch thickness. Panel on "passenger" side of car may be either:

(a) Flat projecting across at approximately the height of the transmission.

(b) Dropped back to level of floor on driver side of compartment.

No vertical section to the driver’s right may be higher that the nominal height of the transmission meaning a "boxed" or flat interior section to the driver’s right is not permitted, except at transmission height.

2-3.4 Hood and Rear Deck Lids

Template hood only. Hood and trunk lids must have positive pull pin type fasteners. Hood must have four pin fasteners on leading edge. Rear deck lids must be hinged or easily removable. Rear deck lid may not be riveted to body.

2-3.5 Dashboard

A full width dash is required on all cars. Vertical surface of dash must project in a single plane across the car. Top (horizontal) plane of must follow the contour of the windshield between the "A" posts. Instruments must be neatly mounted on the vertical panel.

2-3.6 Header and Tail Cover panels

Must match, meaning identical year must be used on front and rear and neither may be cut.

Only Oxford Plains Speedway approved engines permitted. Engines may be interchanged within any corporate manufacturer’s product line. Only ferrous alloy cylinder block type V-8 engines permitted. Camshaft location may not be altered.

Engines accepted for competition under "10.5" type must have a maximum static compression ratio of 10.99 to 1 Maximum. Engines above 11.0 compression limit must use Holley 4412 two barrel carburetor. Aluminum head engine must run 9.5 to 1 Maximum compression, and a 390 cfm carburetor. NOTE: BGN or BGNN Aluminum engines will not likely be permitted because of machine work done to head, cam shaft, etc, refer to rule 2-5.5 and 2-5.6 Check with OPS for further information.

Compliance testing may include one or all three of the following:

(1) Testing by SCS Industries "Whistler" device comparing swept volume of test cylinder to actual combustion chamber volume of test cylinder.

(2) Actual mechanical measurement of swept cylinder volume compared to volume of combustion chamber (cc’ing).

(3) Measurement of maximum 358 cubic inch displacement

2-5.1 Engine Location

Engine must be positioned within the chassis per the following specifications in all competing cars.

(a) Cross (lateral) Location - centerline of engine crankshaft shall be located within one inch of an imaginary line through the center of the car, defined as the dimensional center of a measurement across the car.

(b) Engine height - centerline of crankshaft harmonic balancer (or equivalent) must be located a minimum of 10 (ten) inches above the ground plane.

(c) Front-To-Rear longitudinal location of the engine (setback) is defined as follows.Maximum of 2 (two) inches from centerline of forward most spark plug to determine line projected from ball joints of suspension. Engine must be positioned in normal upright mounting, whereby cylinder vertical centerline of a 90-degree engine shall be a 45 degree engine angle with a vertical line projected from the ground plane.

2-5.2 Pistons

Any flat top piston permitted. Valve reliefs may be cut into piston. Pistons may not exceed engine compression rule.

2-5.3 Connecting Rods

Any after market, but NO TITANIUM or ALUMINUM, connecting rods permitted. Any length rod permitted.

2-5.4 Dry Sump Oiling System

Dry sump permitted. Maximum four stage pump.

2-5.5 Cylinder Heads

Cast iron or aluminum heads, 2002 or older, permitted. Aluminum heads must be 9.5 to 1 compression ratio and use a Holley 390 carburetor. All Heads must be approved by OPS. No porting, polishing, sandblasting, glass beading, or painting permitted. Multi-angle valve grinding permitted. No angle milled heads permitted.

(a) Maximum intake valve size is 2.080 inches.

(b) Bowl work allowed up to ½ inch below top of valve seat.

(c) Port matching allowed up to ½ inch on intake port.

(d) Polishing of combustion chamber only, permitted.

(e) No re-working of exhaust ports permitted.

(f) 10:5 type engine maximum stock compression ratio as measured by Whistler Device, absolute 10:99 to 1.

2-5.6 Camshaft

Any flat tappet camshaft permitted.

2-5.7 Valve Lifters

No mushroom or roller lifters permitted. Lifter bores may be bored, or re-bored and sleeved to accept Ford lifters.

2-5.8 Intake Manifold

All intake manifolds as well as work done to the intake manifold must be approved by the OPS Technical Director. No tapered bore spacers allowed. Max 1" thick spacer permitted.

2-5.9 Carburetor

Oxford Plains Speedway has approved the Holley 600 cfm #4776, Holly 600 cfm HP, or Holley 390 cfm carburetor for competition as follows:

(1) Body of carburetor: NO polishing, grinding, or drilling holes permitted.

(2) Choke horn: Choke horn may be removed with a square cut, no taper or bevel may be cut into the body of the carburetor. The air cleaner gasket ring must remain standard.

(3) Booster: Boosters may not be changed, but may be aligned. Size or shape must not be altered. Height must remain standard. The passageways from the metering blocks may be enlarged to a suggested size of 0.156 inches.

(4) Venturi: Venturi area must not be altered in any manner. Casing ring must not be removed.

(5) Base Plate: Base plate must not be altered.

(6) Butterflies: Stock butterflies must not be thinned or tapered. Idle holes may be drilled in butterflies. Screw ends may be cut even with shafts, but screw heads must remain standard.

(7) Throttle Shafts: Shafts must remain standard and must not be thinned or cut in any manner.

(8) Power Valves, Metering Blocks, and Floats: May be altered.

(9) Throttle Linkage: May be changed.

Any other carburetor must be approved by OPS Tech Director.

2-5.10 Air Filter / Air Cleaner / Air Intake

A carburetor intake air filter or flame arrester is mandatory. Induction to carburetor must be from cowl area. Forward facing or "ram" type induction is not permitted.

2-6.1 Ignition System

A functional battery type ignition must be used. Magneto ignition system permitted. Ignition system must be OPS approved. Electronic box must be visible for routine inspection.

2-6.2 Starter

On board self starter in working order is required.

2-6.3 Battery

Battery may not be located within the driver’s compartment. Battery must be isolated within the fuel cell area of the car. Battery must be covered to prevent spillage if battery is inverted. Battery must be securely mounted.

2-6.4 Electrical Safety Switch

Car shall be equipped with a safety switch that will effectively kill the power from the battery to the car’s ignition system. Switch must be mounted within reach of the driver’s side window opening.

2-7.1 Radiator

Radiator must be located in the stock position and have an overflow protection system so as not to discharge fluids directly on the race track. No antifreeze permitted. A cooling additive may be used.

2-8.1 Mufflers

Mufflers in "as produced condition" are required. Howe #3002, 3006, or H-3018 are to be used. Exhaust pipes must go beyond the driver. Side exit exhaust must be flanged flush to the door panel and no part may extend beyond the door panel. Exhaust must be within 1 (one) inch of the frame rail.

Any carbon fiber or titanium products must have prior approval by Oxford Plains Speedway before they may be used.

2-9.1 Clutch

Multi-disc, designed for racing 51/2" minimum diameter .

2-9.2 Flywheel

Any flywheel permitted.

2-9.3 Bell Housing

Bell housing must be surrounded by a 360 degree blow proof protection covering.

2-9.4 Transmission

No "in-out" type transmissions permitted. Transmission not to exceed four forward gears. Must have at least two forward and one reverse gears in working order. The BERT type transmission without OEM transmission case is allowed and must include dog-type gears. When measured in third gear, on all transmissions used, the transmission shall be 1:23 or numerically higher. Must be 1 to 1 in High Gear. 2 speed Jerico transmissions permitted.

2-9.5 Shifting Linkage

Multi-rod-rod shifter assemblies are not approved for competition. Lever type shifters are mandatory.

2-9.6 Drive Shaft

It is mandatory that two (2) 360 degree steel brackets, no less than 2 (two) inches wide by 1/8 inch thick, be placed around the drive shaft and fastened to the floor or cross member to keep the drive shaft from becoming dislodged and dropping out. All drive shafts must be painted white.

2-9.7 Rear End

Rear end type is optional. However, full floating type hubs with axle retainers are mandatory.

2-9.8. Rear End Gear Rule

Rear axle ratio must remain between 5:38 and 5:67 final drive ratio.

2-9.9 Wheels

Maximum allowable wheel width is 10.0 (ten) inches measured inside the bead. All wheels must be 15.0 inch diameter and suitably reinforced for racing. A minimum of five lugs per wheel is mandatory. Oxford Plains Speedway reserves the right to determine acceptable wheel design/manufacturer.

2-9.10 Tires

Only Oxford Plains Speedway approved tires permitted. Oxford Plains Speedway reserves the right to specify tire manufacturer and type for all events. Refer to Rule 1-38 for the Oxford Plains Speedway tire policy.

2-10.1 Center Section Components

Main frame rail structure of chassis, defined as the primary structure to which rollcage members mount to, must be constructed of a mild steel shape having a minimum perimeter dimension of 10 (ten) inches, 2 x 3, 2 ½ x 2 ½, etc. Main frame rail members shall be a minimum of:

10 inch perimeter tubing: .120 inch wall thickness

12 inch perimeter tubing: .095 inch wall thickness

16 inch perimeter tubing: .083 inch wall thickness

2-10.2 Front and Rear Section Components

Sections extending from wheelbase constraints, front and rear clip sections, must be a minimum of 10 (ten) inches in perimeter. 10 (ten) inch perimeter tubing must go to the rear edge of the fuel cell.

2-10.3 Main Frame Rails Defined

Main frame rail members shall be configured so that the side rails are located within the normal tread width of the car. Frame rails may extend outside a longitudinal line projected between outside vertical surface of wheels. Right side main frame rail may be of perimeter or "straight rail" design. However, if left side (driver’s side) is straight, an approved structure must enclose the driver’s area and be integral with rollcage and side protection rollcage members, constructed of 1 ¾ inch diameter, .090 wall thickness tubing.

A perimeter frame chassis is defined as having left and right main frame rails that are symmetrical (with one inch tolerance) with kick out from front clip to main frame rails on both sides; both frame rails must be constructed of steel with same size tubing on both left and right frame rails; frame rails must measure 56 inches from outside to outside. Frame rails left and right must be a minimum length of 44 inches.

No section of the complete frame may be pierced, drilled, or otherwise altered for the purpose of reducing weight. Absolutely no holes will be tolerated in main frame rails and clip structure except to facilitate component attachment and/or brackets.

2-10.4 Ballast Weight

Ballast weight must be securely attached to main frame rail or major cross member structure. It is strongly recommended that major ballast weight be contained inside the main frame rails. No lead shot or liquid type ballast permitted.

No ballast adjustment devises permitted on car. Weight transfer devises of any type may not be activated by the driver.

2-11.1 Springs

Type and number of springs including height and wire diameter is optional. No barrel or progressive rate springs allowed.

2-11.2 Shock Absorbers

Type and number of shock absorbers is optional. Maximum shock gas pressure is 175 psi.

2-11.3 Sway Bar

Any sway bar permitted.

2-11.4 A-Frames

Independent front suspension is mandatory with articulating upper and lower control arms.

2-11.5 Spindles

Steel spindles only.

2-11.6 Wheel Base

Maximum wheel base is 108 inches. Minimum wheel base is 102 inches. Left side wheel base must be within +/- 1 inch of right side.

2-11.7 Tread Width

Maximum allowable tread width is 66 inches. No tolerances. Refer again to rule 2-2.3.

2-11.8 Body Height

Minimum roof height shall be as per Body template measurements .

2-11.9 Frame Ground Clearance

Absolute minimum height of frame and cross members is 3 inches from the ground before, during and after each race event with driver. No lifting allowed. Rear spoiler height maximum must be maintained before, during and after each race event.

4-12.1 Steering Components

Major steering components must be fabricated from approved ferrous or non-ferrous alloy metals. Steering columns must have a minimum of 2 U-joints. Removable steering wheel is required.

Hydraulically actuated four wheel brakes in proper working order are required. Brake fluid cooling systems permitted.

Only Oxford Plains Speedway approved fuel may be used.

2-14.1 Fuel Cell

Approved fuel cell with all components with a maximum capacity of 22 gallons, U.S. Measurement, is required. Must be enclosed in a 20 gauge metal canister and installed in an approved manner. Refer to diagram section for recommendations for proper installation. A check valve must be installed on the vent line. It is recommended that a fuel line shut off valve be installed in the trunk area. A safety loop designed to protect the rear of the fuel cell is recommended. Minimum ground clearance from the bottom of the fuel cell to the ground plane is 8 (eight) inches.

2-14.2 Fuel Pump

No electric fuel pumps permitted

2-15.1 Roll Bars

All cars shall be required to have a four-point rollcage structure of minimum 1 ¾ inch outside diameter,. 090 inch wall thickness molyendum or mild steel tubing. The rollcage structure shall be fully triangulated with minimum 1/8 inch thick gusset plates utilized at all major tube intersections.

The four-point rollcage structure shall have a minimum of 4 (four) horizontal driver’s side "door" bars, and at minimum a "X" structure spanning the opposite side door area between the front and rear rollcage uprights. A perimeter frame car shall have a minimum of 3 (three) "door" bars on the right side.

Rollcage structure shall be integrated to front frame stub via a "hoop" section surrounding the engine compartment and joining the front rollcage uprights. Rear braces shall extend diagonally from top rear horizontal rollcage members to "kick up" section of rear frame members. Bottom bay of rollcage structure shall have a X-structure spanning between the frame rails. Rear frame section shall have a "X" or oblique members to stiffen frame rails against rear corner impact, lessening parallelogram rollcage tendency of rear rails. A sub-structure integral with the frame and rollcage members shall provide driver seat mounting points. Foot well area of driver’s compartment must have oblique horizontal member connecting forward upright and main frame rails, then braced to engine compartment main hoop.

All major rollcage members including uprights, connectors, "door" bars on left or right side, and major braces must be a minimum 1 ¾ inch, .090 inch thickness tubing as specified above. Incidental structure components for brackets, component mounting, etc., may be fabricated of lighter material. Full circumference, high-quality welds are mandatory on all tube connections.

Rollcage material is subject to sonic testing or inspection hole testing for compliance to these rules. A tester for analysis of frame cage strength may be used repeatedly.

Add 16 gauge metal between door bars and body on driver’s side only. Minimum 40 inches in length and 17 inches high. 16 gauge metal may be welded in between door bars and door bar connectors on driver’s side only.

2.15.1.1 Specifications for Perimeter Frame Roll cages

Material to be used must be DOM or seamless, .090 minimum wall steel tubing. All perimeter cars are required to have 4 (four) point rollcage welded to frame rails. The 4 point or main structure of the rollcage must be symmetrical in all directions. Minimum length for door bars is 42 inches. Total height of rollcage to be 40 ½ inches from bottom of frame. Halo to be no less than 1 (one) inch lower. Width of halo to be no less than 46 inches outside to outside of tubing. Full dash bar required. All cars must have an X-type member across and behind driver. One piece tubing run diagonally or perpendicular between halo in top of cage required. Minimum height of door bars on driver’s side is 22 ½ inches from bottom of frame. Passenger side door bars may be the X’d structure spanning passenger door area. A so called "Petty Bar" must run from center of cage to upper right front halo.

2-15.1.2 Specifications for Straight Rail Frame Roll cages

Material to be used must be DOM or seamless, .090 minimum wall steel tubing. All offset or straight rail cars are required to have 4 (four) point rollcage welded to frame rails. Minimum length of door bars is 42 inches. Total height of rollcage to be 40 ½ inches from bottom of the frame. Halo to be no less than 1 (one) inch lower. Width of halo to be no less than 32 inches outside to outside of tubing. Full dash bar required. All cars must have an X-type member across and behind driver. One piece of tubing running diagonally or perpendicular between halo in top of cage centered is required. Four curved horizontal door bars on driver’s side with a minimum of 8 (eight) inches to edge of seat from inside of door bars is required. Minimum height of door bars on driver’s side is 22 ½ inches from bottom of frame.

Offset or straight rail chassis passenger side bars may be 3 bar X’d structure spanning passenger area. A so called "Petty Bar" must run from center of cage to top right front of the halo

2-15.2 Additional Roll Cage Specifications for all Cars

Roll cage members must CLOSELY conform to window/roof/door contour and not be readily apparent when car is viewed from side area. Rollcage members must be within tube diameter dimensions of actual roof component.

2-15.3 Fire Extinguisher

A working fire extinguisher must be within reaching distance of the driver. Extinguisher must be located on the right hand side of the car.

2-15.4 Part Identification Numbers

Any parts that have any identification numbers and those numbers are removed or altered will be declared illegal.

2-15.5 Non-conforming Parts Penalty

Any parts that are found to not conform to the rules contained herein will become the property of Oxford Plains Speedway and must be surrendered immediately upon demand. Parts will be held by Oxford Plains Speedway and will be disposed of at the desire of Oxford Plains Speedway. If any team refuses to turn over any requested part or parts then that team will be denied access to Oxford Plains Speedway until such parts have been surrendered to the satisfaction of Oxford Plains Speedway management. An additional fine may be imposed as part of the penalty.

2-15.6 Declaration of Intent

Anything not specifically not covered in this rule book must be approved for competition by the Technical Director.

2-15.7 Eligibility

A competitor who competes in 5 (five) or less features in a given division in a given year will be eligible for future rookie status.

IT IS THE RESPONSIBILITY OF THE COMPETITOR TO OBTAIN AND BECOME FAMILIAR WITH THE CURRENT RULES PERTAINING TO THE DIVISION IN WHICH HE/SHE CHOOSE TO PARTICIPATE.