Big bore builds and head gaskets

Posted by Jack Vines On 2011/11/8 14:55:42

I've been collecting the 374" blocks and head gaskets, but these days there seems to be a shortage of brave guys who want big bore builds.

Back in the bad old days, the bench racing claim was any Packard V8 could be bored out 1/4" (.250") My sonic testing indicates this would leave the cylinder walls too thin for such a tall column, but that's another story.

Head gaskets were always a problem for the larger bores. Back in '56 when Hot Rod ran a story on how C-T Automotive bored and stroked the 352" to 414", they couldn't find any 374" gaskets in time.

Boring a 374" .250" over would be 4.375" and there's never been a commercially available gasket that size.

However, the 374" Packard V8 can definitely be bored 1/8" to 4.250". Problem is, the OEM steel shim 374" gaskets are only 4.240" diameter.

In all the years of building these engines, I've only seen one set of Fitzgerald 4.250" bore head gaskets. They are quite different in appearance and execution than the OEM steel shim gaskets.

Anyone else have or have seen the Fitzgerald big bore gaskets. Any other true 4.250" bore gaskets?

jack vines