997 Head Question

[Eric V.]

On another Chevrolet web forum I was helping a guy identify an engine he had in storage. The engine has heads with casting no. 3740997. One head has a casting date of H197 and, according to the owner also has "X58" cast into the side of the head between the middle and end exhaust ports. The only heads I am aware of that had "X58" cast into the side are the 3748770 heads used in '58 production. Has anyone ever encountered a 997 head with "X58" cast into the side? Can anyone explain how this head can exist and what its application might be? The H197 casting date indicates it is probably too late for '57 production. Thanks in advance for info/comments.

Eric Vrem

[William C.]

Re: 997 Head Question

I just gave away a set of 2bbl heads from a 1958 engine, they had the X58 casting on the side

[Paul M.]

Re: 997 Head Question

Eric, I have had a set of 548 and seen others with X58 cast into them. They all had July or August 57 dates.