Routy: It seems I missed the "won't" in your post. Sorry about that.

Bill: I did do some looking, and there seems to be some question about high octane gas burning slower or cooler. Some sites say it does, others that it doesn't. There are sites saying the same fuel burns at different rates in different engines, and that the "same" fuel sometimes burns at different rates in the same engine. There seems to be agreement that different blends burn at different rates. The burn rate also changes with mixture, which changes in most engines with throttle setting. I would have to say it is one of the Great Unanswered Questions.