Unless you're buying an E58 factory 4bbl HP 360, there's no major differences. The 2bbl 360s from like 1975 are no different than the low-performance 360s from 1988. And if you're building one, there's even less concern of what you start with. The 340 cam should be a good step in the right direction but especially if cost's half a consideration, I wouldn't be tied down to year limitations that serve no purpose. The newer blocks tend to have less wear, the ability to run a roller cam w/o extra effort/money is a plus, and running one's an even bigger plus.
