From: "Robert Dervin" <rjdervin@xxxxxxxxxxx> > I need to run 94 octane in my '58 along with a bottle of booster just to > keep the ping out. That is with only 6 degrees BTC initial and only 19 > degrees total advance. Other added advantages to premium fuels are better > detergent, more consistancy and smoother running. > This is a thread that can go on ad infinitum if not ad nauseam. I am interested to know what kind of MPG you are getting on this car with the current engine set up. It seems to me there is no such thing as premium fuel. It is all the same stuff, only the plus and the supreme have additional additives. The latent power is exactly the same. the additives serve to provide a higher resistance to knocking or pinging and that's it. I have never heard of detergent in gasoline, but that does not mean much. I dare to suggest that few people with these engines have to go to the lengths you are going to, Bob, to avoid knock. I certainly do not have to do anything like it, and, as admitted, having been educated in frugality by the Scottish education system and culture, I run 89 octane in mine. Dimitrios tried to show me the benefits of running higher octane gas in the engine with the timing advanced, but I found it to be very unsatisfactory, and was glad to get the backing of engineering reports published in 1958 to provide quantified, objective, analysis on the subject. Objective in as much the report was not created at the behest of either the car or the oil industry. I suspect, Bob, your engine has some significant issues for which the use of the knock suppressing gasoline is only a band-aid. That is why I am interested in your MPG. I am using rough estimates, because my odometer does not work, but I am running at 16 to 17 MPG on the highway in my '58. Stop start traffic kills MPG in the car. It really is scary seeing the needle drop as I crawl along in crowded situations. But, out on the open road, the car runs quite parsimoniously. Hugh 58 Imperial