octane question

what kind of octane increase would you expect to get with mixing a can of the 108+ with 10 gal of 93 octane premium fuel? I'm running 11.1:1 with aluminum heads and iron block on my 557 and thought i might of had some pre-detonation under a heavy load but only heard it once, i was going to try some upgraded fuel to see how it would run and how the plugs looked with it, i'm currently running 14 initial and 34 total on the timing and it is all in by 2200,

thanks
rick

bout equivilant of 94.5 really probably even less, as it doesn't go mathematically.

If you did 5 gallons 108 with 5 gallons 93, figure about equivilant 100 octain.

10 gal of 93 and 5gal of 108 will be about 98 octane.

[(#gal x octane#1) + (#gal x octane#2)]/Total # of gal

ify I figured can as 1 gal,