What is the highest compression you can have on a Chevy 350 and still run pump gas?

10.5 - 1 usually. Some premium gasolines are as high as 94octane. creeping any higher than 10.5 on premium will force you to invest in some off the shelf octaine boosters and to go higher will basically force barrels of racing fuel. OR get a time machine go back to the 80's and get yourself some aviation gasoline. (most were between 129-150 octane) then go nuts. Or maybe your a pilot and you you can get me some. cheers