Won't start

Your vacuum feed to the vcan MAY be the wrong one. There should be 0 vacuum on the timed vacuum port at idle for older engines and carbs.

BUT... some of this depends on year; the later emissions did some odd things with the vacuum timing, and using 'vacuum amplifiers' rather than a direct timed vacuum feed to the vcan. What year car/engine do you have? It is a Dodge Dart Lite or Plymouth Feather Duster? Does it have a hockey puck looking thing up on the valve cover with vacuum lines in and out? And was the engine fully warmed up?