[ngoma]

Especially, as you mentioned the engine was overheated:

Prioritize Your Workflow, the main go/no-go is the warpage. Greenbook clearly describes the specs and measuring method. Are you going to second guess their specs? If it's warped/twisted beyond the limits don't waste your time worrying about fire ring wear or cracks between valves (BTW, less than a nickel width is generally considered acceptable).

Next comes: How are you going to measure the head warpage? I tried with some straightedges bought from HD but was not satisfied because of the lack of accuracy. Best left for a machine shop IMHO.