As you've found out, there are several variations of Kent blocks and I don't know what the differences are. When I was talking to Dave Bean about my motor, it seemed that one difference was the deck height but there are aluminum blocks. I suspect that any of the heads (BDA, TC, crossflow, YBB?, and as I remember from my racing days there was a flat head - no combustion chambers) will bolt up to any of the blocks but that's just an guess. I'd be interested to know what some of them are. Let us what you find out!