Fuel issues at startup

I went to start the 74 Duster the other day and nothing doing. I wasn't getting any gas when i was turning it over. It is a 318 car with a 625 Carter on it.
I primed the front fuel bowls on the carb and it started right up and stays running just fine. I shut it down and started it a few times and it was OK. If it sets more than half a day or so I have to reprime it to get it going and then it runs and starts fine again.:sad2:

What do you think?