you should get some aviation gas or comonly known as "Avgas". It is a 100 octane gas used in air planes, what is nice about is that is has a higher content of lead in it than other gases. It is a hell lot cheaper than racing fuel, mabey 4$ a gallon. One draw back is that it might make your engine run a little bit lean, I not certian but it may concidering that it is used at 30,000 feet. And if your compersion is high and you need a little bit more octane put some octane boots addetive in it.
I have a busa in a Raptor 660 frame and it loves the Avgas.