O.k. Lets start with, "what kind of compression are you running, and how much total timing do you have?" I am assuming that you do not have ridiculously high compression since you are asking about 100 octane, as opposed to 110 or 116. A friend of mine used some octane booster, and it turned his plugs orange, so I recommend against that. I prefer to mix a tank of fuel. My old 10:1 compression 283 used to love a mixed tank of 92-94 with 100. So far I have been running my 396(402)on Sunoco 94 with good results, however, I will probably mix with 100 on occasion. Keep your timing within reasonable limits and mix fuels, and you'll probably be pretty satisfied.