[RoninLB]

I've always run at least 91 as a preventive issue.

I'm able to monitor detonation with a gauge so I just started to run 50/50 91/89 and so far no prob as the fall comes on. I'd like to work towards full 89 for millage purposes as I'm running carbs that have averaged 16-17 mpg. If the 89 works out I'll further work towards 87. So far I'm optimistic that millage could seriously increase.

Generally how the engine is set up and driving conditions determine what's necessary. 110degF desert heat, Rocky Mt's, etc are all types of factors involved for instance.

I'm using an aggressive timing curve with 10deg initial. So far I may be able to get a 25% increase? Sounds strange to me but it's a hopeful maybe. I was getting 25mpg w/ CIS.