ENGINE SPECIFICATIONS for XTREME STOCK CARS:
1. ENGINES PERMITTED: Engines limited to 365 cubic inches and must be in the chassis originally catalogues by
manufacturer. All factory identification numbers and/or part numbers must remain on crank and heads. The
combination of the rods, block and crankshaft used must be in the same combination that factory originally manufactured (i.e. Chevrolet components only with Chevrolet components and Ford components only with Ford
components).
All factory identification numbers and/or part numbers must remain on crank and heads and be visible.
The use of titanium for rods, rod caps, crankshafts or headers is strictly prohibited. It is highly recommended to use a #12AN
fitting or one inch plug in the oil pan for inspection purposes. If there is not one, the oil pan must be removed for inspection.
Needle bearing camshafts, crankshafts and rod bearings are not permitted.
2. ENGINE BLOCK: The engine block must be a OEM standard production block. No aluminum blocks. Only two-(2) valves
per spark plug are permitted. Double overhead cams are permitted. Turbine-driven, big blocks, turbos, blowers, superchargersor offset engines are not permitted. Computer operated or controlled parts are not permitted. Main bearing cap must be iron or steel. The lifter bore must remain stock.
3. INTAKE MANIFOLD: High performance or aluminum intakes are not permitted. Marine-type intakes are not permitted.
4. CYLINDER HEADS: No high performance heads are permitted. Heads must include OEM casting marks. Double humpheads are permitted. No porting, polishing or grinding is permitted. Rocker arm studs may be pinned. Screw -in studs are permitted. Stock rocker arms only are permitted. Roller rockers are not permitted.
a) All heads must have a minimum 60cc. The “cc” measurement of the intake runner of head must remain stock with the exception of matching port.
b) Unless otherwise stated, any cylinder head with evidence of sanding, polishing, relieving, grinding, porting, angle milling, chemical treating, abrasive blasting to the original cast form, will be declared illegal and penalized. O-ringing the head gasket seal area is not permitted.
c) Combustion Chamber: The combustion chamber may not be altered in anyway.
6. VALVES: Only steel or stainless OEM stock valve or aftermarket OEM production replacement valves are permitted. Any spring, any retainer permitted. Only stock valve guide angle is permitted. Relocating valve guides is not permitted.
7. PISTONS & RINGS: Only flat top pistons are permitted with all three piston rings in place. Zero deck piston may not extendabove the block. The ring lances and lowers part (skirt) of the piston may not be altered from the original in any way. Gasporting the piston is not permitted. Floating wrist pins are permitted. Valve reliefs may be cut into the pistons.
8. FLYWHEELS: Stock flywheels and flexplates only are permitted. No lightening is permitted. The flywheel must weigh a minimum of 23.0 lbs. (no exceptions).
9. CRANKSHAFT: The crankshaft must be an OEM factory production. Aftermarket crankshafts are not permitted.
a) Polishing of any kind is not permitted. One throw on the crank must have no balancing holes in it. The minimum weight of the crankshaft must be 46 lbs.
b) Stroke: The stroke must remain OEM stock as currently delivered by OEM with the exception that it may turned a maximum of .040” under.
c) Harmonic Balancer: Aftermarket OEM stock “type” harmonic balancers are permitted.
10. RODS: An OEM production rod with OEM specifications from a engine used is permitted. The modification of rod length is prohibited. Rods may not be polished. No addition or removal of metal other than normal balancing is permitted.
11. CAMSHAFTS: Any hydraulic flat tappet camshaft is permitted. No roller, solid lift, mushroom or “slapper-type” cams. The vaccuum pressure may not be less than 14.00 inches at 1000 RPM before or after the race (no tolerance). No
adjustments will be permitted during inspection. The official reading will be taken from the track gauge only.
Cam Bearings: Must remain as “stock” Babbitt type. Roller bearings are not permitted.
12. CARBURETORS: Only an OEM stock carburetor or OEM replacement may be used. No dual line double pumpers
permitted.