well , the higher octane fuel will benefit a very hot engine because there will be no heat induced detonation . the fuel will only ignite when the plug sparks to ignite it .
I use high octane fuel more often than standard fuel because the car just runs smoother especially in hot conditions .
I drove an old van which had a Rover K-series engine running on 100LL avgas whilst on DZ duties and I can tell you that old engine developed a lot of power using avgas .