High octane gas burns much slower than regular, so it needs advanced timing to prevent exhaust valve damage as it is still burning well past the power stroke. Red hot exhaust manifolds are not uncommon when burning premium gas in an engine designed for regular.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!