IMO there are two issues that could cause the price of a home-built to exceed that of a pro-built stroker.
1. Machine work: Block selection and prep. Does it need cylinders bored/honed? Line bored for crank? Does the block and crank need to be checked and remedied for interference? Do the cylinder heads need porting or stellite valve seats? Before assembly, has the block been checked to insure that all plugs are in place? (On this point, I know of a guy who built an LA but did not check to see if the oil gallery plugs were in place when his block came back from the hot tank. They were not. Consequently, not only did the engine run badly and not develop proper oil pressure, it rather quickly expired. Money and time lost to get a 360 crate engine).
2. Materials: If there is a mongrelization of parts going into the engine, the builder is going to have a better idea of what does not play well together. For a given application, a well-versed builder will know how far to go to get the performance needed at a minimal outlay of funds. e.g. Re-use head bolts or go to ARP studs. In all probability, the pro-builder is going to consistently beat my cost of parts. He may also know of shortcuts that can improve his profit; or cut what he charges me, that I may not be aware of.
Mopar Muscle magazine has run a number of LA motor build-off competitions. Check them out to see if one matches what you are wanting to do. IIRC, Muscle Motors has done well in a number of the competitions. All of the contact information and a lot of the specs of each engine and builder are in the article. Like any sub-contracted work, get a few recent references for similar work to see if these are people with whom you can do business.
