GM 3964291 Big Block Chevy Rectangular Port Heads Closed Chamber L78 LS6 No Porting
 

This is a pair of original GM cylinder heads for a Big Block Chevy Engine. The casting number on each head is 3964291. These heads are the high performance version with rectangular intake ports and closed combustion chambers. These heads were used by GM on late 1969-1970 L78 396/375HP, L71 427/435HP, and 427/425HP(450HP) L72 engines which were used on Yenko and COPO cars. These heads were also original equipment on the 1970 LS6 454/450HP engines. They were also used as a direct replacement for casting numbers 3856208, 3873858, 3904391, and 3919840.

These heads are in good original condition as shown. They were pulled off a good running engine to replace with aftermarket aluminum heads. They are complete with valves, springs, retainers, rocker studs, and guide plates as shown. The heads have no porting in the intake or exhaust ports. This is a very nice pair. Unfortunately, some dill weed ground off the casting dates, hopefully because they were 1971 or later dates, not just unmatched dates. Either way, the dates are gone and are located under the valve covers so they are not seen when installed. As I said above, these came off a good runner. That said, I'm sure rebuilding them before install would be a good idea. This is an awesome set of heads.

$1350 plus the ride

Thanks,


Jason