[DavidNJ]

One thing that is a lot different now then in the 60's is the availablity of aftermarket parts. Blocks, heads, cranks, rods, pistons, etc. Back then, custom pistons were expensive, rods even more so, heads rare and block non-existent. Now, crank, rods, and pistons are so inexpensive it is hard to justify not using new parts. Ditto heads. That leaves the blocks. And for a serious performance effort, unless the rules restrict it, most builders I know use aftermarket blocks (except for GM LS and Ford Modular motors, for which they don't exist). Please let me know if your experience is different.