Yeah, I saw the photos that you posted after I posed my note, thanks for the extra info. What, specifically, are the few structural differences that you speak of? I was under the impression that there were no structural differences in the block.

Back in the late 90's, my S38 block developed cracks so I rebuilt the engine (which is where the above photo came from). While I was looking around for options, I came across one of the well known US engine builders that was rebuilding S38 motors, and using modified M30 blocks to save some $$$$, but I can't remember who it was now, it's been 8 long years since then.

John