Four things that you didn't mention, Rick, regarding your 'G' cylinder heads that may be of interest to those considering purchase:
1) If you changed to stainless steel valves, what was done to the valve guides? Bronze valve guide liners installed or another approach?
2) What did you have done for valve stem seals? Original style umbrellas or did you have positive valve guide seals installed?
3) Are the 'G' heads posted or unposted?
4) What is the thickness of the pads below the cylinder head exhaust ports and adjacent to the spark plug holes? When new from FoMoCo the pads measured 1.000 Knowing how much the heads have been cut is a factor as relates to whether the heads are posted or unposted.
Ready to bolt on heads are a plus. Understanding what you've got is a 'key', too.
Hope this additional info. will help to match you with a buyer.
NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York