A shade tree fix might be to take a portable belt sander to the head surface while the manifolds are off, but you'd need to unscrew the two dowel pins at the ends of the exhaust ports to get a full stroke with the sander. If you only need to surface it a few thousandths that might be a possibility.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!