305 Sprint Rules
1. DRIVER AGE REQUIREMENT
Driver registration is open to persons 14* years of age or older. Age requirements are subject to change. All drivers who are less than 18 years of age must have all required releases and waivers on file at L A Raceway. (New releases and waivers must be filed each year.) * Drivers under the age of 16 must have two years of prior racing experience.
2. DRIVER’S SAFETY EQUIPMENT
Driver’s Safety Apparel:
Driver’s fire suit (minimum SFI -5 rating) multi-layer or single layer in conjunction with Nomex underwear; a Nomex hood; Nomex socks; fire retardant driving gloves, shoes and neck collars. Driver safety apparel must have the rating tag/label intact.
Full face helmets with a face shield. Helmets must be SNELL SA 2000 or newer certification. Helmets must have the rating tag/label intact.
Driver’s restraint systems must have a five or six-point configuration, with secure attachment to the frame or roll cage. The shoulder belts should be attached to the frame or roll cage at a point below the driver’s shoulder height. The shoulder belts cannot be attached to the seat, body work or fuel tank. Driver restraints must, at a minimum, be composed of (a) two 3 inch shoulder belts, (b) a 3 inch lap belt with a metal to metal quick release mechanism, and (c) a 2 inch anti-submarine strap. Belts can be no more than 2 years old and must be in good condition. Driver restraint equipment must have the rating tag/label intact. Head and neck restraint highly recommended.
Any competition rated arm restraint is required.
Use of a rock screen made from a minimum of .090 screen size is highly recommended but not required.
3. FUEL SHUT-OFF VALVE:
A fuel shut-off valve is required within reach of the driver while sitting in the car with the restraints fastened. The shut-off valve must be marked in a recognizable manner. Vinyl or plastic fuel lines may not be used.
4. ENGINE RULES
305 Chevrolet blocks only. See list of casting numbers in Table 1 (below). Casting numbers must be visible and unaltered. Maximum bore is .060 for a maximum bore of 3.796. Any flat top piston is allowed. No titanium valves or rotating parts. No aluminum or titanium connecting rods. Water pumps must be OEM style. No crankshaft mounted or electric pumps allowed. No computer operated or controlled parts, fuel systems, ignition components, etc. No roller cams. No roller hydraulic cam. Cams not to exceed 0.555 lift at valve. Lifters stock diameter 0.842.
Wet sump only. No external oil systems. The oil pan must have an inspection hole of 3/4 inch minimum diameter and 1/2 inch maximum extension. Location is optional, but the tech officials must be able to view crank throws and rods from this hole.
5. CARBURETOR OR FUEL INJECTION
One (1)4 barrel maximum 750 cfm. 1 11/16 inch throttle bore maximum. No work allowed in venturi to increase air or fuel flow. Venturi must measure 1.410 maximum. No work on throttle plates. Fuel injection is allowed. Injection can be no larger than 2 3/16 inches. If sleeved, sleeve must be minimum 3 inches long and measure 2 3/16 inches through out. No down nozzles. Only one nozzle per cylinder. No part of carburetor or injection including air cleaner allowed above hood. No electric fuel pumps.
Must be stock appearing with 3.48 stroke. No undercut counterweights. No knife edging.
Any General Motors 305 head listed in Table 2 (below) may be used. No VOR-TEC. No center bolt. No unshrouding valves. No porting or polishing. No angle milling. No titanium valves. No shaft rockers. No port matching on heads. Maximum valve sized 1.94 intake 1.50 exhaust. Casting numbers must be plainly visible and unaltered. Must be 23 degree heads.
8. FLYWHEEL AND STARTER OPTIONAL
If you do not have a starter, it will be your responsibility to get your car started and on the track. We will not wait on you!
9. EXHAUST SYSTEM
Must be mounted in such a manner as to direct exhaust gasses away from cockpit and away from areas of possible fuel spillage. Mufflers are required.
10. BATTERY AND IGNITION SYSTEM
Magnetos, Point Style only. No breakerless. No MSD. No crank triggers. No rev limiters. No traction control. Battery must be securely mounted and fully enclosed. Gel-cells recommended and gel-cells need not be fully enclosed. Must have battery disconnect switch.
11. BODIES & FRAMES
Sprint car tail, hood, side panels, and floor pan are required. Body parts may be fiberglass or aluminum material. Must be sprint car appearing. Roll cages and chassis must be constructed of seamless steel tubing that is at least 1.375 inches OD. All chassis and roll cage components must be bent to shape without crimps or creases. The recommended minimum wall thickness is .093. Aluminum frames are not allowed. The top of all roll cages must be a minimum of 2 inches higher than the top of the driver’s helmet, while the driver is seated in a normal driving position. Helmet catch nets on right side of cockpit are optional.
Engine must remain in front of uprights. Firewall required between driver area and engine. Bumpers and nerf bars are mandatory and must be securely mounted. Front bumper must be aluminum or steel. Rear bumper must be steel 1 inch O.D. .085 thickness minimum. Nerf bars 1 inch O.D. .085 thickness minimum (aluminum or steel). They must be bolted on (no cotter pins). Nerf bars must not extend beyond the outside edge of the tires. Opening on right side of cockpit must be a minimum of 10 vertical inches.
Solid Grade 8 or better bolts , (no hollow, gun drill ,or tubular bolts)must be used to attach all steering components. Cars must have a quick disconnect steering wheel. Tether on steering arm recommended but not mandatory. All suspension systems must be mechanical. Cars cannot have shock absorber or suspension adjustment mechanisms in the cockpit.
Computer operated or controlled chassis adjustment parts or components or chassis component adjustable through any form of electrical assistance are not allowed. Electronic traction control of any kind is not allowed.
Quick change rear ends only. Steel torque tube safety loop securely mounted to frame is required under the drivers seat.
14. WHEEL BASE
Minimum wheelbase is 83 inches, maximum wheelbase is 90 inches. Measurement will be from the center of the front hub to the center of the rear hub on the shortest side measured.
Disc brakes only. Minimum of one operable front and one operable rear brake. Inboard brakes are allowed. No carbon fiber rotors are allowed.
Alcohol or pump gas only. No octane, nitro or other performance additives allowed. Upper cylinder lubes are allowed. Fuel lines must be steel or braided line through the cockpit area. A fuel cell with a bladder is mandatory. The tank, fuel cell and bladder must be securely mounted. Fuel hydrometer readings for alcohol must not exceed .796 and .750 for gas corrected for temperature. Fuel checks may be run at anytime. Fuel samples may be taken for analysis and prize money may be withheld until results are known. It will be the responsibility of the participant to remove any cover or cap on the tank for the purpose of obtaining a sample for a fuel check.
17. TIRES AND WHEELS
Sprint Car wheels and tires only. Right rear must be Hoosier SC-25 or Hoosier ASCS Medium 105x16x15.
Top wing mandatory. Not to exceed 25 square ft area. Width not to exceed width of rear wheels. Wicker Bill not to exceed 1 inch in height measured from the upper wing surface. Side boards not to exceed 30 inches high x 72 inches long. Right side board cannot obstruct drivers view in normal running position. No hydraulic wing sliders allowed. Wing cannot be adjustable from cockpit while car is in motion. No pneumatic air cylinders allowed. Front/Nose wing are allowed, but not mandatory. Surface area not to exceed 24 inches long by 37 inches wide. Side board maximum 12 inches high by 24 inches wide. No wedges or foils underneath race car. No pieces may be added to the basic frame as to resemble, imitate or be specifically designed to deflect, trap or form a wind break of any nature, except those used to cool or protect the motor and braking system.
Minimum weight car and driver will be 1550 lbs after race.