just got me a '67 Barracuda

RedFish said

IF blocking the air horn makes it run better you definately have a vacuum leak.
A bad PCV valve can cause all the symptoms you described also since it works on vacuum. If you have vacuum operated choke breakers , or spark advance, or power brakes, start pinching rubber hoses with pliers to rule them out or discover the culprit. Good luck
Also... IF the fuel air mixture is wrong ( vacuum leak ) there will be a timming place where it will run
but poorly.

Click to expand...

So if I close the choke valve a bit when it's running warm, the idle does smooth out, but not 100%; still kind of has a hiccup, but very subtle. I replaced the PCV valve, and cleaned out the oil breather really well. I've tried pinching off every hose I can find (vacuum advance, brake boost, PCV), and the engine dies when I plug any one of those. The carb gasket is brand new, and tight. I think if it is an air leak, it has to be in the manifold or gasket...:scratch: