Must be factory correct for the year, model, and horsepower claimed. Dealer-installed engines and dealer-performed engine modifications are not allowed. Casting numbers must be correct for the year and horsepower claimed including intake manifold, heads, and exhaust manifolds. Head modifications are prohibited, including, but not limited to, porting, bowl cutting, gasket matching, oversized valves, etc. Heads can be cut to help achieve the allowed compression over advertised. Blocks do not have to be "numbers matching," but they must be the correct displacement. Overbores up to .070" are allowed. Stock cranks only. NO strokers! Random P&G checks are possible. Lightweight cranks and connecting rods are NOT allowed. If found, you will be banned from the event until corrected! Aluminum rods are NOT allowed. Smaller-than-stock rod journals are NOT allowed. Aftermarket pistons are allowed, but piston rings can be no thinner than 1/16", 1/16", and 3/16" for top, second, and oil rings, respectively. Gas porting of pistons NOT allowed. Metric and pressure-back-type rings (dykes, head land, etc.) are NOT allowed. Torque straps allowed.
Compression Ratio Limits
All Engines – 1.5 extra points allowed over advertised. Contact us so we agree on the advertised compression.
Engines with factory dished pistons will be allowed to run either a smaller dish, a flat-top piston, or a small domed piston to achieve the maximum allowed compression.
Engines with factory flat-top pistons will be allowed to run a domed piston to achieve the maximum allowed compression.
Engines with factory domed pistons must run a dome of equal or greater dome volume than stock to achieve the maximum allowed compression ratio.
Heads can be milled and blocks decked within reasonable limits in combination with above to help achieve the maximum allowed compression ratio.
The transmission must be correct for the year, make, model, and horsepower claimed. Shift improver kits are allowed. Aftermarket shifters are not allowed. No manual valve bodies. Lightweight purpose-built, drag racing transmissions NOT allowed (for example Pro Trans, Kilgore, etc.). Just switching to aluminum drums is illegal. Anyone caught will be banned from the event until corrected! Torque converters must be within 1 inch of the stock outside diameter. Maximum stall limited to 2200 rpm. Higher stall speeds will require factory documentation.
The transmission must be correct for year, make, model and engine of the car. 3-speed manuals may be upgraded to the correct 4-speed if originally available. Aftermarket H-pattern shifters are allowed if no modifications to the floorpan are necessary. Line locks are not allowed. Scattershields are okay. No conversions from column-shift to floor shift allowed unless available as a factory option. Aluminum flywheels are NOT allowed.
The rear axle must be of the same manufacturer as the car. Any gear ratio is allowed. Lightweight driveshafts NOT allowed.