high octane gas

[Brickren]

What are the dangers of using aviation gas in a normally aspirated engine? Would running it straight harm anything or should I run it 50-50 or some other mixture be recomended?

[Stekay]

I wouldn't use the term danger. The higher octane burns slower so if you don't want to advance the timing to take advantage of it, you'll lose a little power. It's also a bit more aromatic so it cools a bit better. The only thing you'll hurt is your wallet. With 100LL at $6/gal and auto gas at $3/gal, unless you're trying to just use some up, it doesn't make much sense.