i am running a carbed 5.0 in my 65 mustang. it has a roller cam so i used a rebuilt distributor for a 85 carbed 5.0. it came with a vacuum advance. i still have to dial in the carb and timing, but when i hook up the vacuum advance to a port on the carb or to the intake manifold, it drives really rough, bogging a lot when i accelerate. when its not connected at all, it runs a lot better but still has a little hesitation when i first take off or at high rpm. what do you guys think the problem is?