Probably good advice for some, but first, I wouldn't trust just any machine shop to assemble anything of mine, sepecially heads, and second, if they're worth a damn, it won't be cheap. Anyone can throw a set of heads together, but to properly assemble a set, knowing spring installed press. and installed height, stem seals on right (or at all), springs right side up, properly crushed before checking, clean, etc, is all important. Do a few sets of your own, and you've paid for a good compressor. Or not. That's one of those "buy once, cry once" tools that are worth their weight.
Damn...after all that, I'm thinkin I need to step up!! :idea: See what you got mew into JCRebel!!
Yep, the guy I bought the boat from had a reputable shop build this BBC, well they left about .015 retainer to seal clearance (based on the cam THEY installed), my new PC seal cutter just arrived today so I can correct that problem. I prefer to do as much of my own work as possible, here in Seattle we have a 3 month boating season, my hobby isn't boating, it's wrenching!
SC, I think you need to step-up too, sell me that crappy old Mac compressor. I got another cool tool today, Comp's crank socket (#4797), it has a knurled nut on it to hold a degree wheel, I haden't seen these before