The plans to build up the engine are looking grim now. I cleaned up the heads a little before sending them out and here's what I found.
The cracks are on all four cylinders and numbers three and four are heavily coated in oil/slime. It's a little hard to see in the picture, but between the prechamber and valve seat it's cracked, and heading out on the other side of the prechamber. The other head is also cracked, but is oily only on cylinder one. What would cause this to happen? Or is it the cracks?
Should I still bother to send these out to be pressure tested and checked over? If these engines turn out to be a boat anchors would a 240D engine from a 115 chassis bolt in? I've got a line on a complete running unit locally, and may go that route.