A '67 Head Case

[Patrick T.]

I have a very late (July 15th) 67 L-79. The NCRS Spec Guide lists the head part numbers for both 300 & 350 hp heads as #3890462. Both of my heads were cast on F-9-7 (June 9th), which is only 3 days after the block was cast. These dates seem logical considering the build date, but both of my numbers are #3917291, which is listed as a '68 head. Apparently GM was already casting heads for '68 production. Is it possible that some of these heads could have ended up on late '67s ? Any input would be appreciated.

[Scott Marzahl]

Re: A '67 Head Case

I went through this myself with my '67 L-79. At the time I talked to Roy Sinor the '67 judge. It is acceptible for late cars to have the 291 heads with the boss for the temp gage. The boss area was later drilled and tapped for the '68s.

[Joe L.]

Re: A '67 Head Case

Patrick-----

The GM #3917291 cylinder head was used on both 300 hp and 350 hp 327s in late 1967 production. This cylinder head actually went into production in the late first quarter of 1967. It was produced in both 1.94/1.50 valve size for 300 hp and the 2.02/1.60 valve size for L-79s. Some VERY late heads installed on 67s MAY even have had the temp sender boss actually drilled and tapped, but plugged with a hex-head pipe plug.