Let the machine shop handle the disassembly of the head. Remove the rocker arm assembly only, and be aware that it will try to come apart in the middle. Machinists hate to deal with basket cases! Depending on how often the valves have been reground before, the shop might regrind them again, or reccomend replacement. There needs to be a minimum of 1/16" "margin" after regrinding at the edge of the valve where the taper meets the edge, not a knife-edge bevel which would burn away almost immediately. Ditto for the valve seats. If the head has been reworked a couple of times already, the seats might have been ground deep enough to need replacement. The valve guides will also need to be checked for wear, and sleeved or replaced as necessary. A good-quality machine shop will evaluate all these things and give you a cost estimate before they begin the rebuilding job.
If you can't find a machine shop in Knoxville that you're comfortable working with, contact Glen Prost, the owner of Headworks of Nashville. He's one of my father's former students from the late 1970's, and he's very familiar with older engines and what it takes to do a good head rework on them. I've done business with him for 30+ years with no problems whatsoever.
Jerry
