a shop called westchester crankshaft grinding
Engine Rebuilders, Engine Machine Shop, Engine Parts, Cylinder Heads - New York Engine & Machine Inc.
says $550 and up to rebuild a om617.
of course metric motors got me paranoid that my head could be cracked, even from overheating mildly once when the water pump went. it wasn't severe enough to need a new thermostat, based on the fact the heat is still working as it was before, and the temp gauge seems close to standard...
so it's kind of a Q of trying to have the head redone vs replacing with a rebuilt...