I can vouch for what Mr. Davis said about the squish band needing a slight angle inward. Several years ago when I was younger and dumber I bought one of his heads for a Fox .60. Due to a MFG tolerance on the Fox cylinder that was off a little the piston hit the part of the head that protrudes into the cylinder. Well, Genius Hobbs hadn't heard of head shims so I proceded to sand the head down so the piston would not hit, and in the process removed the squish band and made head perfectly flat on the bottom. I ended up with an engine that ran hot and was all but impossible get running correctly. Lesson learned.