I got this 425 Forged Crank, out of my 67 425 Bock. I had it hot tanked, magnafluxed and mic'ed. I put a small gouge in a journal during disassembly some how. Machinsit says it ought to clean up just fine at .010/.010. It does have some rust on the throws/counterweights. How important is it to get all of that off to use the crank? Most seems to be surface rust that may come off with a wirebrush, or maybe whoever turns it will clean it up better. I am just used to seeing the real pretty cranks for a rebuild. This is one is not the prettiest crank I have seen. I thought there was also a bad spot on the crank, but the machinist said no, its just a bad spot during manufacturing in the mold, the the crank is fine and that spot can be used for balancing the crank. I took his word for it. He says many times Forged cranks do not turn out as pretty as Cast cranks. I did not know that.

 

I'd want to get the rust off the crank before I installed it if this was my engine. Its just one more possible source of a particle that could somehow get into your journals or thrust surfaces. It might not be likely that a particle of rust would get into a journal or thrust surface (it would likely get filtered after falling into the oil pan), but it is a possible failure mode that could be eliminated with an hour or two of work.

Give your machinist a call and ask if they clean it up prior to machining (included in the price he quoted)? Might be cheaper for you to wire brush it and maybe pressure wash it yourself before you take it to him (if its not included in his price).