posted January 18, 2005 11:48 PM
i dont know if your familiar with the cam coupees, they run a 305, ill see if i can post the engine rules,
Only 305 cubic inch Chevrolet (GM) engines are permitted. Maximum overbore is
.060 meaning a 315.07 cu. in. maximum is allowed. No one piece rear main seal
blocks are allowed. Only blocks using the two piece rear main seal are allowed. Block casting numbers are (78-79) 460776, 460777, 460778, 361979, (80-84) 14010201. 14010202,14010203, 14016381.
2. Valve springs must be stock GM chevrolet or equivalent. They cannot exceed
120 lbs. on the seat when tested on the engine. Valve spring diameter must be stock
for 305 engine, with a maximum of 1.250" diameter.
3. No vacuum leaks between the intake valve and the top of the carburetor.
4. Intake Manifolds must be stock GM quadrajet spread pattern, cast iron or aluminum.
No angle cut, milling, grinding, acid dipping, coating, welding, port modification, or
hole relocation beyond basic stock street car rebuild allowed. No modifications
allowed except blockage of heat riser and EGR holes. No bow tie high performance
or after-market manifolds allowed. Quadrajet carburetor attaching bolt pattern is a
rectangle with dimensions of 4 1/4" x 5 5/8".
5. Cylinder heads must be GM stock 305 cubic inch heads. No special after-market
cylinder heads permitted. Only 2 valves per cylinder, intake valve maximum of 1.84"
permitted. Exhaust valve is a maximum of 1.50". No special valves or valve sizes
permitted. Swirl stainless type valves allowed but no polished valves allowed.
Cylinder heads limited to a minimum of 53 cc combustion chamber. No interior
deburring or polishing permitted. Studs may be pinned or screw-in studs (no guide
plate permitted). Poly locks okay. No angle cut heads or excessive grinding, milling,
acid dipping, coating, welding, port modification, or hole relocation beyond the basic
stock street car rebuild. three angle valve job is permitted. Casting numbers must
remain in head, if they are missing, the head is illegal. No vortec heads of any kind.
6. Crankshaft must be stock 3.48" cast iron. No racing cranks allowed. No polishing of
crank counterwights allowed. No knife-edging of crank allowed. No one peice rear
main seal crankshafts allowed. All crankshafts must use the older style two piece
rear main seal. Engine must have stock 305 OEM harmonic balancer. No after-
market fluid dampers or any other after-market harmonic balancer allowed.
7. Rods must be stock 5.7" GM rods. Aluminum rods prohibited. No steel racing rods
allowed. No polishing of rod I-beams allowed. No 6" rods allowed.
8. Pistons may be either flat top or stock GM pistons. Cast type pistons allowed. Flat
top pistons must have four valve reliefs in each piston. Cast in piston at time of
manufacture. Any type piston rings allowed. Must have minimum of two
compression rings and one oil ring. Floating wrist pins are allowed. No coating of
pistons allowed. Engine block permitted a minimum of .0 deck clearance. Piston
must not hit straight edge held over cylinder while engine is cranked with starter.
9. Camshafts must be hydraulic only. Cam may be indexed. A .450" lift camshaft may
be used with 1.5" ratio rocker arms and is legal. If 1.6" rocker arms are used, you
must not have more than .450" lift at the valve or its is illegal, meaning you must
have a camshaft with less lift. If lift is checked at valve, a .005 tolerance will be
allowed. Hydaulic lifters only.
10. Rocker arms must be stock stamped, steel configuration and only 1.5" or 1.6"
allowed. No aluminum or other roller rocker arms. Valve lift cannot exceed
.450" with either 1.5" or 1.6" rocker arms when measured at the valve.
11. Engine displacement formula for determining cubic inches is: Bore x bore x .7854 x
stroke x number of cylinders = cubic displacement. Any engine exceeding
maximum allowable cubic inch displacement limit will cause disqualification. Only
305 cubic inch Chevrolet (GM) engines permitted with a maximum over bore of
.060", which results in 315.07 cubic inches.