What gains are to be had on raising compression, only to pull timing out to compensate for too low a octane fuel rating?
Yes it will run on pump gas after timing changes...
IMO this combo will be counter productive, and wont be optimal..
I wouldnt bother with shaving the heads..
I would rather run optimal timing with a half point to a point less in compression, than run the compression up there and pull timing out, and fight detonation.
Have you thought about E85 which is a pump fuel?

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