Since you did not fill out your profile, I have no idea what track(s) you run. Some tracks require a certain fuel, bought (usually) from a station near the track. Other tracks only go by what the rule specs allow. Still, other track allow racing fuels. Depends on the track, the tech, and how fussy they are about the rules. On average, a 98 octane fuel will do the job (depending on your jetting). Do a quick search on the site for fuel. There are a few threads dealing with the subject.
Steve