I have wondered the same ?? to get the ocatane up to 100 where it is recommended for HI comp. engines.onelunglow said:How about this question then... Say you did motor work and put a 11:1 piston in. They say you should run premium gas. Can you buy the cheap stuff and add octane booster? OR what about a 12.5:1, they say 110 racing fuel. What about premium and some octane booster?