Chassis

1. A sprint car is defined as a racing vehicle of single seat design, built upon a racing chassis and mounted on four racing wheels. No rear engine cars or aluminum frames allowed. No box tubing frame rails.  Driver’s compartment shall be separate from the engine by a firewall of suitable material.

2. Allowable wheelbase of 85 to 90 inches.

3. Steel front axles only. Rear axles may be aluminum.

4. Must have front and rear brakes in working order.

5. Maximum wheel diameter 15 inches. No plastic wheels. Wheel covers
must be securely fastened. Titanium or carbon fiber brake rotors are
not allowed.

6. A Hoosier right rear tire is required.

7. No cockpit adjustable shocks or weight jackers allowed.

8. No TITANIUM, only nerf bars and bumpers made of steel at least one-inch in diameter will be allowed. Nerf bars, which offer adequate protection in the event contact with another car, are mandatory. Nerf bars must be bolted or roll pinned to the vehicle. No pop rivets may be used to fasten nerf bars, bumpers or wings. Nerf bars may not extend
past outside of tires.

9. Approved fuel bladder required. No carbon fiber fuel tanks.

10. Hoods are mandatory during racing.

11. Total weight of car and driver may not be less than 1,500 pounds.  Weigh in to be after any event or qualifying. Weight to be measured as car comes off of the track in the condition that it took the checkered flag. No bolt on weight.

12. All cars must utilize either a driveline strap or a driveline hoop restraint constructed of .065 steel either welded or bolted to the chassis. Metal hoop restraints must react positively to magnet testing. The rear cross member used for mounting the steel driveline hoop must be constructed of .083 steel.

13. Drag links must utilize 4130 steel of at least 1” in diameter and a minimum wall thickness of .058. Tie rods and heim ends must be made of steel only. A magnet must stick at all times. No swedging of the tubing will be allowed.

14. Drag link must be tethered to the frame.


Engines

1. Cast iron blocks are mandatory.

2. 358 cubic inch maximum displacement.

3. Flat top pistons only – no domes or dishes. Zero deck height.

4. Maximum compression ratio of 10.75:1 as checked by whistler gauge.

5. Maximum 3.5 inch stroke. Weight of crankshaft not to be less than 46 pounds.

6. Cast iron heads of stock configuration mandatory. “Stock OEM valve guide angle, no relocating valve guides.” No raised intake runners or spread port exhaust. Porting into runner ¾” to match manifolds is allowed. No port and polish. Ford Windsor heads may have the exhaust ported except the valve guides.

7. Intake port may be matched to the intake manifold or gasket, not to exceed a depth of ¾”. Intake valve may not exceed .060 inch over stock valve size, i.e. 2,020” stock – 2.080” maximum. Exhaust seats may be back cut under valve seat with a maximum angle of 75 degrees.  No grinding or acid etching under the valve seat will be permitted.

8. Exhaust port may be matched to gasket or header, not to exceed a depth of ¾”. Exhaust valve size may not exceed .025 inch over stock size, i.e. 1.600” stock – 1.625” maximum. Exhaust seats may be back cut under valve seat with a maximum angle of 75 degrees. No grinding or acid etching under the valve seat will be permitted.

9. Grinding in the combustion chamber will be permitted. Welding in the combustion chamber will be permitted for repair purposes only. No welding to reshape the combustion chamber. The combustion chamber will be defined as beginning with the head gasket area and ending at the top valve seat. This is to allow the participant to meet the 10.75 to 1 compression limit and allow the competitor valve jobs to be performed to meet specifications outlined in intake and exhaust specifications.

10. No modification allowed to heads that would allow use of down nozzles or multiple spark plugs per cylinder.

11. Must be naturally aspirated. Fuel injection or carburetion allowed.  Timed and/or electronic fuel injection units are prohibited.

12. No V-6 engines.

13. No titanium, plastic or carbon fiber components for crankshaft or rods.

14. Piston must be flattop with the top of the piston square to the bore of the cylinder.

Wings

1. Front Wing – Maximum size to be 6 square feet total with a maximum width of 36 inches. Center Foil must be square or rectangular in shape with all four corners set at 90 degree angles. 12 x 26” maximum side panels with ½ inch maximum turnout at a 90 degree angle from foil. A 1 inch wickerbill permitted at back edge of foil.

2. Top Wing – Maximum size to be 16 square feet, must be one piece.  The deepest point allowed on the top surface of the wing is 2 ½ inches measured from the top of the wing to the bottom edge of the 1-inch turn up (wickerbill) at the rear edge. Center Foil must be square or rectangular in shape with all four corners set at 90 degree angles with
no variance allowed. 

Top wing side boards maximum size, 66 inches long and 30 inches tall. The top 2/3’s of each top wing side panel shall consist of only 2 corners. Each corner shall be set at a 90 degree angle with no variance. This portion of the side panel’s leading edge cannot be behind the center foils leading edge. Panels must be of one-piece construction. Panels must be fabricated flat. Turnouts on all edges of the wing must not exceed 1” x 2” and must be orientated at a 90 degree angle to the flat portion of the side panel. Side boards must be mounted square to the center foil and parallel to each other with a ¼ inch variance allowed.

3. Side wings, rear wings or rudders are not allowed.

4. All wings must be fabricated of metal alloys only, no fiberglass, plastic or carbon fiber. No split wings or bi-wings.

5. Wings cannot be adjustable from cockpit.

6. No car will be allowed to compete without a top wing.

Tire Compounds

1. Tire compounds legal for competition at Williams Grove Speedway will be Hoosier SC12, SC15, SCRD15, SC25, SC55.

Fuel

1. Methanol only according to Federal Standard of Purity, Grade A or AA. No additives of any kind including top lube will be allowed in the fuel.


Body

1. Body should give the appearance of completely covering the car’s frame and should be fully painted. The hood or cowling need not enclose the sides of the engine. One-piece tail and fuel tanks permitted, must be streamlined. No side foils, rudders or panels are to extend beyond roll cage on any side. No body pieces to extend beyond or underneath front torsion tube except hood. Normally accepted sprint car body rules.

Miscellaneous

1. No two-way radios or other means of electronic communications.

2. No mirrors of any kind may be used.

3. Drilling of any bolts, fasteners or heim ends is prohibited. No hollow fasteners allowed.

4. The use of electronic logic processors (this includes traction control devices) to control any function of the race car, and/or any system for continuous gathering of data from any function of the race car for which intended use is computer downloading, is strictly prohibited. (Penalty: Loss of Driver/Owner points for the year and loss of earnings for the event infraction was detected)
 

Suggested Safety Equipment

1. Arm Restraints

2. Driving uniforms, flame retardant with a minimum of two layers.  Underwear, head sock, gloves, foot socks and shoes should all be flame retardant.

3. Driver’s seat fume deflector / heat shield.

4. Fuel Shut-off Valve.

5. Full face Snell approved helmet – no more than 2 years old.

6. Head rest padding.

7. High-back (stock car style) seats.

8. Kill switch in reach of driver.

9. Knee pads or padded steering.

10. Minimum 3 inch wide seat belts, no more than 2 year old, mounted to frame with bolts or looped over frame tubes, belts traveling through bottom of seat. Minimum 3 inch wide shoulder harness, double over the shoulder, military shoulder straps with anti-sub
crotch belts. Harness to go over horizontal tube located less than three inches below the top of driver’s shoulders.

11. Neck collars.

12. Right head net or support. Head net equipped with a quick release capability.

13. Seats mounted to the frame with a minimum of three bolts.

14. Windshield screens are highly suggested with a minimum of .090 screens.

ANY CAR, TEAM OR DRIVER NOT MEETING WILLIAMS GROVE SPEEDWAY SPECIFICATIONS, OR STANDARD RACING SAFETY PROCEDURES AND EQUIPMENT, IS SUBJECT TO AUTOMATIC DISQUALIFICATION AND /OR PENALTIES.
 

Racing rules to be normally established and instituted rules of Williams Grove Speedway. For additional information or clarification, please contact Williams Grove Speedway at 717-697-5000 or by mailing
1 Speedway Drive, Mechanicsburg, PA 17055.