I would argue that in most cases(at least as it pertains to the many sets I’ve had here in the shop), that would be the least of the “issues”.

Every time I had a set here, there would be some new anomaly I hadn’t seen before.

The norm was widely varying valve depths and chamber volumes, guides with almost .003 clearance ootb, rocker stands machined to different heights, intake surfaces not milled parallel to the dowel pin c/l, chambers that were wider than the fire ring on most head gaskets, head dowel pins too far apart....... and the list goes on and on.

Then, many times after all of the particular heads you’re working on have had all of that stuff remedied....... after they have been in service a while........ the seat rings start moving around in the heads....... often, a lot.
I know of one case where after shut down, and a heat soak....... an exhaust seat actually just dropped out of the head.

If you got everything sorted out........ on certain combos....... they could make pretty good power.

The least problematic were the Zeus castings.
The few sets of those I’ve had here didn’t really require anything except fairly normal prep.


I have some pics of what I believe are unfinished castings that Chapman would get....... sort of.
I don’t think this version of the head, other than those finished by Chapman were ever offered for public consumption.

The pics look like heads that would get cnc ported, but they have the spring pockets cut real deep, like the original version.