Got word back from my engine rebuilder- seems my old head is TOAST and two of my pistons were fried. It's a wonder I was able to get the darn thing off the highway. I may keep the old (matching numbers) block- if I end up using it, it'll have to be sleeved, since some PO had already had it rebored. (News to me.) In the meantime the machinist is going to tear into my spare 1592 and see if he can use it. If this doesn't pan out, I may be pulled toward the DARK SIDE...