12.5 to 1 What octane do you run!!!

Took my car out for its last stomp at the track yesterday. Diluted my racing fuel 50/50 (91/107). Raised timing until i lost MPH. It likes 40 degrees total timing. No ping or knock, plugs look good. Air was real good. Adj altitude was between 7767-8014' all day. Got my best et so far dropping it from a 8.27 to a 8.22 and finally (after letting it breath with open exhaust) 8.19. 60 foot time dropped for 1.92 to a 1.87 and MPH went from 83.5 to 85. when i opened up my exhaust, I realized i was plenty save on my jetting tune! All in all a grate day, sucks the season is over. Have a question but will start a new thread for that one.