I rebuilt my Autolite 2 barrel on my 68 Cougar a few months back since the car had sat for a long time. It kept changing RPMs while at idle and I assumed it was a vacuum problem. After replacing all vacuum lines and not fixing the problem I took the car to a mechanic who is supposed to be good at engine issues. His comment was that unmetered fuel was flowing from the carb and so it would need a rebuild. The cost is too much to have someone else do the rebuild (might as well buy a new one). Since I'm the one who rebuilt the carb I am trying to figure out what I might have done wrong. I would like to fix this myself if possible and am willing to buy another kit if I need to. Any ideas? I had heard that there might be an issue with the manifold gasket since this was a NAPA kit.