I agree that these mounts are similar for the same types of engines, but there are some subtle differences. For example, I found mounts in the boneyard that fit both the 305 and 350 small block chevy's, but larger engine blocks likely have a different mount.
I cheated by looking at catlogues from companies that furnish high performance mounting blocks (e.g. PSC) to get a sense of their shape before heading to the boneyards.
