Big Block Heads

[Peter J.]

Can anyone ID a set of aluminum big block heads with a part # 3946074 and a date of 2/25/72? Thanks, Pete

[Joe L.]

Re: Big Block Heads

Peter-----

These are fairly common cylinder heads. Not because a lot were used on cars, but because a LOT were sold over-the-counter. These are aluminum heads which were first used on late 1969 L-88s and ZL-1s. They were next used on 1971 Corvette LS-6s and that was it as far as their use on a PRODUCTION vehicle. The heads which you describe, having been cast in 1972, were certainly never used on a PRODUCTION engine. They were originally either sold over-the-counter or were part of a SERVICE engine assembly.

These heads have the open combustion chamber design with 118 cc, nominal, combustion chamber volume. They have round exhaust ports, rectangular intake ports, and 2.19/1.88 valve size.

Although these heads have cast iron valve seat inserts, like all aluminum heads, the inserts are NOT hardened and they are NOT inter-locking.

[grr]

Re: Big Block Heads

Joe's right, my book shows open chamber aluminum 114.8cc or so,2.19 intake/1.88 exhaust, engine use 427 and 454,years 69-71 for production line use,last used on 454 in 71 production line 425 hp engine. So Joe's scoop about the over the counter checks out vs actual production line use on engine applications. PN.3946074.Look like a good set of heads.grr#33570

[Peter J.]

Re: Big Block Heads

Thanks Joe and Grr I found the 1971 usage in one of my books but couldn`t find any match for -72 now I got it.