I have an idea which one that might be, and we can just carry on and pretend it isn't there if that'll help.

Being that potentially useful content is somewhat lacking these days, in my humble opinion I'd like to see some discussions kept alive if possible.

TBH I forgot my intake closing point long ago, but on my 451 which
has aluminum heads and .045 quench, 10.75:1 measured, I'm at about 175lbs cranking compression and don't hear or see any detonation
on local E10/93. I have not noticed a huge difference in performance or tendency to detonate between 34, 36, and 38 total timing.

Of every grade of normal street gasoline available, I feel 93 is the most likely to be discontinued/obsoleted in the future and this
made me comfortable building my future 572 with 10.2:1.