13:1 Compression Pistons in 340 Small Block

Lol! I’ve got a key to my airport fuel pump as well. An 8:1 mix works really well with the ethanol free 93 plus premium we have available here for 10.5:1. Luckily, our ethanol free station is owned by someone who has an old car habit, so he mixes the Sunoco premium additive package to the rich side. It’s probably 96 octane or better, it smells like 100 octane race gas.