So does ignorance, you don't keep running it while its rattling like that, and if raged edge builds are your aim....you better damn well know how to tune for that octane and have a good ear.
I did spend a lot of time playing with the ignition timing, seemed like every year or so I was backing it down a degree or two more than the previous year even running the same grade from the same station (I know still varies). Last I had it was 32* total all in at just under 3000 RPM. Head gaskets were Fel-Pro 1008s. Cranking compression was 170-180 psi on all cylinders taken just this past summer, pretty substantial for 5000' above sea level I think.
Looking at head gaskets now, same situation it was 7 years ago... if I want the ideal quench with a .030-.035" compressed height I gotta pay 2x as much for Cometics. Fel-Pros only come in .039" and .028" which I think would be pushing it (would it?). It's all speculation anyway heck I'll probably want new pistons.