1967 BB Heads

[Dave Stafford]

Is there any difference in the earlier #3904390 heads, and a later '67 version that ends in #802? Both are oval ports and fit the stock 390-400hp set up for 1967 .

[Joe L.]

Re: 1967 BB Heads

Dave-----

I don't believe that there is any functional difference between the early and late cylinder heads and I don't think that there is any significant design difference. Unfortunately, at the moment, I don't recollect what the differences are, but I'll try to post later.

[Joe L.]

Follow-Up

Dave-----

As it turns out, the only difference in the GM #3904390 casting and the 3909802 casting involves a change in combustion chamber design. The '802' cylinder head had the combustion chamber slightly enlarged in the vicinity of the spark plug. As a result of this change, the combustion chamber volume increased from 98 cc, nominal, to 101 cc, nominal.

When I responded to your question earlier I had this vague recollection regarding the difference being the addition of a temperature sender fitting. However, I wasn't sure enough about that to so-advise. Good thing I didn't since neither the '390' nor the '802' have temperature sender bosses added. The THIRD (and last) design 1967 oval port head, GM #3917215, did, though