Sorry for the abrupt 1st response;

- My car runs about 10.75:1 and with the cam I've got and the unported 906's, I expect the cylinder pressures to be too high for pump premium. Initially I thought of the octane boost in a can too (104+ is the brand that came to mind) but after a little research and talking to the guys with the same setup as mine, I realized I'll need to run race gas or at least a race gas/pump gas mix.

My understanding is that the octane boost in a can is good for only incremental increases like 1/10th of an octane.

If things are borderline, retarding the timing may be enough to stop the detonation.

My car isn't finished yet, but the plan is for a 50/50 mix of race gas and pump gas.

Hope this helps,

Dave