What kind of gas is running in your whizzer? This question is more open to everyone. I used to run the lowest octane, 87. Now with all the mods and higher compression i'm thinking of running 89.
You are still fine with the 87 octane even with the mods. The increase in compression (if you have one of Quenton's shaved heads) isn't high enough to make the change to a higher octane necessary.
I have a 60-thousandths shaved head, lightened mushroom lifters, timing advanced, opened restrictor and the hi-flo exhaust insert, and I'm doing fine at 87 octane.
Adding to my last post, a buddy of mine does use 100LL aviation fuel in his Whizzer, but he had a bunch of mods done and prefers to ride his at WOT all the time.
One suggestion I will make is to try to find gas without ethanol in it. The gas with ethanol just gunks up everything in no time. If you cannot find gas without ethanol, make sure you put Sta-bil in the gas you do use. I even suggest that with the good gas as well.