a. Engines are interchangeable between manufacturers line such as: Chevrolet body/Ford engine; Ford body/Chevrolet engine; etc.
b. Stock steel block only. Maximum engine displacement is 362 c.i. (372 c.i. in Chrysler). Minimum engine displacement is 350 c.i. (340 c.i. in Chrysler). Maximum block sizes are as follows: Chevy 350, Ford 351 and Chrysler 360. Blocks may be cleaned and deburred. Oil returns may be plugged or screened with wire only. Valley pans permitted between block and intake manifold. Internal engine painting allowed (oiled areas only). Bowtie and SVO blocks are not allowed. No internal powder or ceramic coatings allowed. Headers are the only engine components that may be insulation wrapped.
602 350 cu in 350 hp 390 ft lbs torque 9:1:1 compression
604 350 cu in 400 hp 400 ft lbs torque 9:6:1 compression
c. Heads: All parts listed below must originate from stock production castings and forging which have been machined according to the normal machining schedule utilized for standard production parts.
Cylinder head Number of valves per cylinder
Type of combustion chamber Location of spark plug
Orientation of spark plug Arrangement of valves
Valve location in relation to the cylinder
Angle of valves Type of valve actuation
Number of intake ports Number of exhaust ports
Center distance of intake ports Center distance of exhaust ports
Shape of intake and exhaust ports at mating faces of manifolds
Angle of port face relative to mating face of head to block
and the firing order
All cylinder heads must be approved and all modifications must be submitted before any modifications will be eligible for competition. Approved manufacturers identification and part numbers must remain on the part being used in competition. In order to be eligible, the cylinder heads must meet the following requirements:
1) Cylinder head must be a stock cast iron production only, limited to two (2) valves per cylinder. No titanium valves or valve springs are permitted. Only steel valve springs are allowed. No port matching or flow work is permitted. No angle cutting of the head to the block mating surface will be permitted. The head stud or bolt holes cannot be off set or drilled off center for the purpose of moving the head in any direction.
2) A maximum of three (3) angle valve jobs are permitted. When cutting the valve seat angles, no stone or grinding marks are permitted above the bottom of the valve guide. All cutting in reference to the valve job and bowl area must be centered off the centerline of the valve guide. No radius cuts permitted. Upon completion of the valve job, the bowl area under the valve seat down to the bottom of the valve guide must still be in the same configuration as far as shape and finish as it was from the manufacturer. Surfaces and/or edges where the cutter or stone has touched must not be polished. No hand grinding or polishing is permitted on any part of the head.
3) Only Chevrolet part numbers 14011058, 10134392 and 12480034, casting number 14011034, heads are permitted on GM models. The Chevrolet head part number 1051108 is NOT eligible. Chrysler W-2 heads are permitted. Any stock production cast iron head is permitted on Ford models. Ford part number M-6049-N351 cast iron cylinder heads are permitted. A spare set of heads which is compatible with the OSP Street Stock Division head rule may be approved for temporary use by the officials.
4) All valves must be identical in appearance and construction as an OEM type valve. No polishing or relieving behind valve face at stem. No neckdown valves. No air directional devices will be permitted on any valve surface. Valve stems must have a minimum diameter of 11/32 inch. Any valve stem seals and retainers allowed. Heads may be cut to receive larger diameter springs. Roller rocker arms allowed with poly lock nuts and stud girdles. No dual shaft rockers allowed. Screw in studs and guide plates allowed. The maximum valve size as measured across the face of the valve are as follows:
General Motors Intake 2.020 Exhaust 1.625
Ford Cleveland Intake 2.190 Exhaust 1.710
Ford Windsor Intake 2.020 Exhaust 1.600
Ford M-6049-N351 Intake 2.020 Exhaust 1.600
Chrysler Intake 2.020 Exhaust 1.625
5) External Changes: External modifications will not be permitted. All cylinder heads are limited to a minimum 62cc combustion chamber. The combustion chamber may be machine cut, beside the valves only, to equalize the chamber cc. No other machining or grinding will be permitted. Internal polishing, porting and/or any other internal modifications will not be permitted. Only steel lifters are allowed. No ceramic or ceramic buttons.
d. Crankshafts: Only approved standard steel or cast iron crankshafts permitted. If aftermarket crankshafts are used, they must be identical in appearance and construction as an OEM crankshaft. Stock stroke only (3.48 on GM; 3.50 on Ford; 3.31 on Chrysler). Balancing is permitted. Counterweights must be the same shape, may be polished, but they cannot be knife-edged, undercut or drilled to lighten the crankshaft. The rod bearing journals may be drilled. The main bearing journals may not be drilled. When weighing crankshafts, the minimum weights listed below shall include the timing chain sprocket. Chamfering of oil holes allowed. Only standard OEM steel elastoner-type harmonic balancers permitted. The following dimensions are the minimum specifications for all crankshafts:
Rod Journal Weight
GM 2.100 minus .030 50 pounds
Ford 2.100 minus .030 50 pounds
Chrysler 2.100 minus .030 50 pounds
e. Pistons and Rods: Any flat top piston is allowed. Valve reliefs may be cut into pistons. Minimum piston to deck clearance is .005. Only approved steel connecting rods permitted. Titanium or stainless steel connecting rods are not approved for use.
f. Camshaft: Any solid lift camshaft except roller tappet or mushroom allowed. Stock diameter lifters only. Mushroom or roller lifters not allowed. Any timing chain and gear allowed.
g. Intakes and Headers: All intake manifolds must be approved. Any aluminum or cast iron intake allowed. No high rise manifolds allowed. All manifolds must remain as manufactured. No port matching or flow work permitted. Any headers allowed. Breather element maximum of 4 high. Standard round breather elements and cans only. No substacks, velocity stacks or any air directional devices allowed. Any headers allowed and they may be powder or ceramic coated. Front half of breather element may be shielded with sheet metal.
h. Ignition: Any ignition is allowed. No magnetos.
i. Oil Pan: Any wet sump oil pan is allowed with any cam driven oil pump located in the oil pan is allowed. Oil coolers allowed.
This is what I build engines to for specs. Circle Track has these engines complete for a price at the specs you want 602--603--604
We have one track that allows 383 with rev chip --this should keep you busy for a few min. before you build get the specs (Fine print included) before you spend.. Tracks are fickle when you get in these spec engines------------------- Have Fun
