Just my opinion, but if you're not sure about the condition of the rest of the motor, rings, cyl. walls, etc. a head gasket doesn't cost that much. I'd yank the head off and put that sucker on the bench where I could comfortably work on it. Then you can clean the combustion chambers, clean the valves, inspect the guides, I believe the guides should have about .0015" clearence? H.R.L. will correct me if I'm wrong.
Then you can take a look at the cyl. walls and get a better idea what's going on. You'll be able to "feel" if the vavles are too sloppy in the guides. Wiggle the valve head side to side, you'll know if it doesn't feel right.
Besides, layin' over top of those big fenders kills my back!
