Where'd you hook up the vacuum gauge? Did you try over-retarding and over-advancing distributor while watching vacuum gauge? If you're not getting varying readings on gauge then something ain't right. Assuming your timing marks are correct, you might try bumping it up a couple degrees from spec. then bolt it down and start zeroing in on the carb. The carb rebuilt also? After setting timing, did you play with the mixture screw while checking vacuum readings? You wanna go as lean as possible without affecting performance. Well, I guess maybe answer a few of these questions and we'll all go from there.
-David
