[Craig Hendrickson]

Originally Posted by fiedlerh

I believe Pontiac bore spacing is 4.620
Mfr Bore Spacing
Packard 5.000
(snip)

You bring up a good point that I was talking to Tom Vaught about tonight.

The Packard V-8 was brought out the same year as the Pontiac and Chebbie, i.e., 1955. The Packard was a very physically large engine that was "designed" to eventually be bored/stroked out to 500CID. As it turned out, the largest production displacement was 374CID in 1956 and there was a 1957 prototype extant that was supposedly 440CID.

Another interesting point between Packard and Pontiac is that John Z Delorean worked for Packard from the late 1940s until sometime in the early to mid 1950s. He was primarily a transmission engineer, but he certainly would have seen Packard's plans for their V-8 while "hanging around" the engineering department.

There are other similarities between the Packard and Pontiac V-8s such as the center Siamesed exhaust ports, a separate valley pan, Delco electrics, etc. I once had a conversation with Pete McCarthy about these similarities, which Pete explored, and he came to the probably correct conclusion that there was no "cross intellect" going on between Packard and Pontiac during that era despite Delorean's mutual employment.

If Packard had continued beyond 1956 and "fixed" some of the design problems with their V-8 then no doubt it would have been one of the outstanding wedge valve V-8s of the early 1960s. It certainly had the ability for large displacement, but then again so did the Caddy 500CID.

It's all moot at this point, but thanks Tom for bringing this subject up.