I had the motor and trans rebuilt in 04, stock cam, rear axle is 3.00, the guys that rebuilt it asked if I wanted 289 or 302, I asked for 289, I did have a vacuum leak and pulled the manifold off to fix it and pulled my vavle cover while at it and discovered 302 heads, so I havent looked at the crank yet but assuming its 289 with 302 heads, Ive found a couple other people thats happened to, some say they breathe better, not sure what up with that. while the manifold was off I took the carb apart and checked floats, needles and cleaned it all out. I put the manifold back on yesterday morning, used "the right stuff" gasket maker in the valleys, started it that night and checked vacuum still steady at 15in, I sprayed carb cleaner everywhere trying to find a leak and no change at all in idle. my dizzy is the original (new insides, had a shop adjust points gap) dual advance, retard is plugged (before I got it) and the advance is on the carb where there is no vacuum at idle. how do I know if my advance is busted? if I pull the line off while running and suck on it the motor picks up.