I have run 100LL avgas in my ZDZ, Zenoah, Quadra, and Brison and have noticed no ill effects.
I have not measured any engine temps.
Perhaps someone will check the temps using decent probes and gauges(not a temp gun) for us.
Full size automobile engines are designed to run on pump gas(mogas) and 99.9% of them are 4 cycle engines.
I have run several full size airplane engines on avgas and mogas and have noticed no difference in the short term.
The aircraft have egt and cht instrumentation on board.
In the long term I have seen engine damage caused by mogas.
Mogas doesn't burn as clean as 100LL in full size aircraft and leaves deposits on the exhaust valve and puts more crap into the rest of the engine thru blow-by.
I've been twisting wrenches on and flying full size for over 30 years...haven't seen everything yet!
I use whatever fuel in my model engines that is easily available...usually 100LL because it smells much better than mogas and is easily available.
The weight of 1 US gallon of 100LL is 6.01 lbs@ 15 degrees Celsius as per FAA and Transport Canada approved info.

Good Luck
Happy New Year
John