In this thread, several people have said that cracks between the valve seats on a Subaru EA82 cylinder head won't affect performance, so I've decided to go ahead and use the heads I already have and hope for the best. I've already bolted one head back onto the block, and I quit working on it today before I could tear the other one off completely--prolly have it off and back on tomorrow. Then I gotta order some new gaskets and other parts from Checker, and get a few more from the junkyard, and hopefully it'll be done in a week or two.