I don't mean to be a smart azz, but let your machine shop do what he wants to do. I don't mean that directly about the guy you talked to, but just in general. If you're on a budget make him give you a list of things he wants to do and a firm estimate. Have another machine shop do the same.
I guess what I'm saying is find a machine shop you trust and let them do what they're suppose to do and that is build you a motor that will last!!
BTW there can big a huge difference in $ from one shop to another.
I've used two different machinist over the last 5 years. Both did really good work, but there was a BIG difference in $.