[tbirdtbird]

with this much trouble at this point I would mill the head in question even if it is brand new. I would also consider that the deck may be warped and the engine may have to be pulled, taken apart, and hauled off to a machine shop for a slight cut. Then reassemble with the Felpro 7013 non-silicone version (anyone around here who has tried the silicone has had them fail early for whatever reason, so I have refused to try one) using the techniques already explained including 2 good sprays with Permatex copper coat.

I agree the pressurization did not contribute to failure but I still maintain it is unnecessary. I tour all over the place, 1000 miles at a clip, Mitchell, and never have a problem. The model A engine is so inefficient at fuel combustion that a quick warmup is never a problem. If you live in Alaska I suppose this could be different but in that case just use a stat