I use e85 and really like it. I'm in Washington now and it's a little hard to find, and they do winter blending down to around E70 I think. I can't run 70 because I've got 15.9 static. 85 is about it for me, and compared to gas I use almost 80 percent more. I know the average is around 40, but if you can dump more in and burn it it'll make more power. My jetting changes with the same mix from perfect mine shaft air to hurricane depression baro dramatically. 8- 138 drill size alky jets to 8-175 drill jets in 2 1250 dominators is the range I've been in. I think the real problem is with 2 big carbs there isn't a great deal of carb signal, making it harder to jet. I haven't found a consistent A/F ratio that it makes best power at. In good air 12.8 works and in bad air 11.7 reading for gasoline. It does like a little more timing than gas. For me it was around 2 degrees more. From what I've seen with other motors on the dyno the less efficient the head the more timing it takes to see real improvements. Sometimes as much as 7 more degrees helped with lower compression average headed motors.