I never said I was going to run without vac advance,,,, You guys assumed, I was merely trying to answer to some questions I had floating around in my head and was trying to understand it too... Ive read multiple times about getting horrible mileage with mechanical advance, that's why when I rebuilt my distributor I put a new vacuum unit on it. Thank you guys for all your help in this matter. I learn sometimes it just takes a bigger hammer and a lots of beating for me to get it.