'69 BB Heads

[Dan 80]

The NCRS Spec Pocket Guide only lists the 3931063 cast head for the 390 and 400 hp BB's in Corvette. Likewise in the Summer '85 First Edition, First Printing '68-9 Judging Manual. Yet Alan Colvin's book lists the 3964290 casting as well as the 3931063 for '69 and '70 390 and 400 hp Corvette as well as other hyd. cam Chevys.

I have a pair of 3964290's dated G 28 9, and G 11 9. A previous owner told me they were from his '69 390 horse convertible.

Did Chevy use the 3964290 castings in late '69's or just in the '70 model year?

[Joe L.]

Re: '69 BB Heads

Dan-----

Although the 3964290 heads are generally considered to be 1970 model year cylinder heads, if these heads were, in fact, originally installed on a Corvette, it almost had to be a late 1969 build 1969 model. Keep in mind, that for 1969, the production of that model year continued through December, 1969. So, these cylinder heads, cast in July, 1969, and if they were originally used in a Corvette, could pretty much only have been used in a 1969 model.

The "sticking point" here is the fact that, having been cast in July, they could also have been used in some other Chevrolet model which had its 1970 model year changeover at the usual time.

However, I really think that the 3964290 heads were used on late-build 1969 Corvettes with L-36 and L-68 engines in the same manner as 3970010 350 blocks were used in late-build 1969 Corvettes.

[Terry M.]