Why is there 440source but no "360source"?

True but my emphasis is on heads nobody's kicking around spare aluminum SBM heads in their shop. If other parts are so plentiful then why not heads? It would save people a lot of money to be able to buy all their SBM parts from one supplier instead of buying from multiples, or a "resale" type company like Hughes. Yes they do make/modify some of their own parts but they don't have a dedicated manufacturing facility anything like 440Source.

One thing got me thinking about this as well, I was reading up on Caddy 472/500 engines and obviously nobody makes parts for them... but there's a company out there now that makes EXCLUSIVELY Cadillac engine parts (everything to build one from a bare block pretty much) like 440Source and they seem to be very successful.

Really gets on my nerves how it's cheaper to build a 440 with aluminum heads and other modern performance parts than a 360 with the same kinds of parts.