I forgot to mention, I picked up another block yesterday, had one 8CM head, other missing, and someone took the crank out years ago(left pistons and rods). I thought I found a good Merc block.
It didn't look too bad, but had been sitting outside for a long time. Well I was dissapointed when I pulled the one head and found massive rust in two cylinders. So much that when I flaked it off I discovered deep pits in the cylinder walls.
I think it's too far gone for sleeving, but it will at least let me practice drilling the hole and tapping for the full flow oil system.