Al, is E-85 available in your area? It would be worth the minor modifications involved, to run 110-115 octane for about $3.00/gallon. I know this, because I run E-85. High-octane fuel here is also at least $6.00/gallon, and I decided to try it after the pump premium fuel I was running, climbed to over $3.50/gallon, with no end in sight. I will not go back to gasoline. Corn likker is much more fun. As for the immediate change in performance, yes, it does mix right away. Fuel pouring into a confined space through a small opening tends to do that. I was able to increase my initial timing from 14 degrees to 20 degrees, with just the change that you have done to yours, in the fuel department. Switching to E-85, I found that I can run 18 degrees initial, with a huge gain in performance, akin to the 20 degrees and 50/50 premium and 110 octane fuel. Just a few thoughts to get your brain wondering.