Starting troubles/carb spacer ???

First of all i apologize if this seems like an easy fix but i am very new to the problem solving end of owning and fixing a car. I have a 1974 Plymouth Duster. it has a 318 with a Edelbrock carb/intake setup. i'm having troubles w/ my car starting. after i get it started and run it if i shut it off for just a few minutes it will fire most times as soon as i turn the key. but if it sets much longer then that it cranks and cranks i have to pump the throttle and choke it. i've noticed after it sits awhile the fuel filter drains and there is no fuel left in it. someone told me to put a spacer between the carb and intake. a phenolic spacer. i've looked at them and they offer 1" and 2" and 4 hole and one large hole . so if anyone can tell me if this will or could help my issue and which spacer to get. that would be great. thanks