Fuel Octane

[fastd]

SPO1715,
So that ratio of 3 @ 111 and 10 @ 91 yields a 95.6 octane. That works best for you? What compression is your engine?
When you used straight 111, you said it ran like crap at the top end; what is your top end defined as? At RPMs above a certain level? Or MPH above a certain level?

How did it run at the low end?

[HI Cobra]

Here in Hawaii we have the 92 octane with 10% ethanol. I have a 351w
with the aluminum heads - 405 hp. Ran ok but I started adding 1 gallon/10
of 110LL avgas and what a difference that made in the higher gears. I have
the .64 5th and the minimum I could drive it in 5th on the flat and level was
65. With this blend 55 is no problem and I can leave it in 5th going up H3 at 65
where before 4th was a necessity. Mileage went up by about 3 mpg too. With a 3.27
rear this blend made the 5th a lot more useable for me for cruising.

[RET_COP]

Lucas Octane Booster is sold at autozone. I found this to be a quality booster and will treat 25 gals. I read from many sources that it will raise 91 Octane to about 93 at that ratio but you can add the bottle to less Gas and up this number another point or so. Its not that expensive for the insurance it provides. I have 10.5:1 static Compression and my motor runs great at 34* total timing.
Lou