If you just want good basic machine work, I've always been happy with Clarks machine shop in Cupertino. They are not Pontiac experts or race experts, but do good basic work and have been around a long time.

You can save a lot of money by researching and designing an engine yourself, based on an expert's experience, like Nunzi's or Jim Hand, then have a place like Clarks do the machining, and you do the assembling.
However, if you're looking for all out race, with Dyno testing and tuning- sorry, don't know anyone.