Wow. I didn't realize just who much the wrong vacuum advance could screw things up. Although now that I think about it, it seems pretty obvious.

I recently had to replace the intake manifold due to stupidity on my part. While I was at it, I went ahead and rebuilt the distributor with all new shims, etc. Bubba had installed a set of craptastic weights from the recurve kit, so I got ahold of a donor distributor and scavenged some factories. The donor had a practically brand new vacuum advance can where as mine looked kinda rough, so I swapped them out too. Boy was that a mistake.

I couldn't get a smooth idle, no matter how much I fiddled with the carb. I kept thinking there was a vacuum leak somewhere that I had missed. It finally dawned on me when I reconnected the advance hose that my idle jumped up 500 or more rpms, and that by the time I backed the idle screw down to where it should be, it was running like total crap. I couldn't have broken the tires loose if I'd wanted to.

So after a week of driving like that, I swapped the cans back out. Lo and behold, everything went back to running the way it was supposed to. It's amazing how much trouble a single brain-fart moment can cause.

 

I know I am there right now with my brand new motor