64 Plymouth 273 Intermitent severe misfire.

That's what I'm asking for. Some real diagnostic tips. Compression as far as I know won't cause an intermittent severe miss, or maybe you're just throwing that in there for extra pokes.

I'm not poking anything. What if there's a broken ring? It can seal sometimes and sometimes not. Same with a partially burned valve or a worn guide....Hay, do what you want. My car runs great.