Trouble running when first starting

I have a 1973 Plymouth Duster /6 with a 1920 Holley carb.

In the morning i go out to start my car and it starts right up no problem, then is starts to idle real bad. If i don't keep it revved up then it dies and takes for ever to start, But once shes warmed up then she runs just fine. Then after she sits for like 2 or more hours she does the same thing again. What could cause this and what can i do to help stop this kind of behavior. Its really annoying!!:cussing: Ive already done all the plugs and wires and cap and rotor, adjusted the fuel mixture, adjusted the idle and the timing, What else can i do?