I had the exact same problem with my '57 235 and thought the same thing was happening with fuel leaking out either through the carb or the fuel pump after sitting for a few days. Exact same symptoms as you describe.
Rebuilt the carb and replaced the fuel pump. Same issues.
I now do exactly what red58 mentions above using the choke out full after tapping on the gas a couple of times when the truck has sat for a few days regardless if it is cold out or not. Problem solved.
Matt
