"Scott" == Scott writes:

Scott One thing I think "might" be a concern is that burning
Scott 100LL (can't get 80 octane avgas these days) in an engine
Scott built for 80 octane is the extra heat.

Eh? Where's this "extra heat" come from? There is no practical unit
energy difference between different octane fuels.
--
"You, Mr. Wilkes, will die either of the pox or on the gallows."
-The Earl of Sandwich