REVISED 2008 RULES DENOTED IN RED, BOLD, ITALIC TEXT

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 or aluminum frames allowed. No box tubing frame rails. Driver’s compartment shall be separate from the engine by a firewall of suitable material. No carbon-fiber body parts.
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 of 15 inches. No plastic wheels. Wheel covers must be securely fastened. Titanium or carbon fiber brake rotors are not allowed. 6. Any racing tire is allowed.
6. All right rear tires used must be a HOOSIER National Sprint spec tire, size 105/18-15. Any SC compound tire is permitted. Left rear tire max width sidewall to sidewall is 19-1/2". Left rear wheel max width is 15 1/4 inches..
7. No cockpit adjustable shocks or cockpit adjusted weight jackers.
8. Nerf bars must be steel and offer adequate protection in the event of contact with another car are mandatory. Nerf bars must be bolted or roll pinned to the vehicle, no pop rivets.
9. Approved fuel bladder required. No carbon fiber fuel tanks.
10. Hoods are mandatory. The rib may not extend higher than 2-1/4 inches.
11. Drag link must be tethered to the frame with nylon webbing of at least 1 inch width.

1. Cast iron blocks are mandatory. GM steal heads must have 23º valve angle.
2. 358 cubic inch maximum displacement.
3. Flat top pistons only, no domes or dishes and top of piston square to the bore of the cylinder. 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 valve guide angle, no relocating valve guides. No raised intake runners or spread port exhaust. Porting into runner 3/4 inch to match manifolds is allowed. No port and polish.
7. Intake port may be matched to the intake manifold or gasket, not to exceed a depth of 3/4 inches. Intake valve may not exceed .060 inch over stock valve size, i.e. 2.020" stock - 2.080" maximum. Intake seats may be cut back under the 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 3/4 inch. Exhaust valve size may not exceed .025 inch over stock size, i.e. 1.600 stock - 1.625 inch 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 of the valve seat. This is to allow the participant to meet the 10.75 to 1 compression limit and allow competitor valve jobs to be performed to meet specifications outlined in intake and exhaust specifications.
10. No modification allowed to heads that would allow the use of down nozzles or multiple spark plugs per cylinder.
11. Must be naturally aspirated. Fuel injection or carburation allowed. Timed and/or electronic fuel injection units are prohibited.
12. No V-6 engines.
13. No titanium, plastic or carbon fiber components for crank or rods.
14. Total weight of car and driver may not be less than 1500 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. Weight measured by speedway scale. If a car fails to go directly to the scales when required to do so, that car will be disqualified.

Wings

1. Front wings - Maximum size to be six (6) square feet total with a maximum width of 36 inches. Center foil must be square or rectangular in shape with all four corners of foil 90 degrees. Side panels maximum size 12" X 26" with a maximum of a ½" turnout at a 90 degrees from panel. A one (1) inch wickerbill permitted.
2. Top wing - Maximum size of sixteen (16) square feet and must be one piece. The deepest point allowed on the top surface of the wing will be 2-1/2 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 of the foil at 90 degrees. Side panel must be one piece with a maximum of 66 inches long and 30 inches wide with a 1 X 1 turn out on the front edge and the top and bottom edge. Rear edge of side panel may have a maximum turnout of 1 inch out and 2 inches toward the front of panel. Top 2/3 of side panel must have two corners each at 90 degrees with no variance. Front edge of side panel cannot be behind the lead edge of center foil.
3. Side wings, rear wings or rudders are not allowed.
4. Wings can not be adjusted from cockpit.
5. No car will be allowed to compete without a top wing.
6. No part of wing may be mounted past outside edge of the tire.