Fuel Delivery Problem on my 74...this is wierd?

[74Chevy74]

Ok guys here is a wierd one... I just picked up this chevy last week I drove it home for 30 miles ran fine, drove it to work the next day and it was ok, then I got home and later had the truck idling in the driveway and it stalled? after that it would'nt start anymore? I unhooked the fuel line that goes to the carb, to test the manual fuel pump and cranked to see if it was getting gas, and it wasn't. I got this truck from my buddy who just put a fuel pump on it like 6 months ago, wll I pulled that all apart check things out, played with the fuel pump and it seemed to have vacum/pump, and put it back together.

After that I tested it again with the line unpluged from the carb so now I had fuel? so I drove it to my buddies house about 2-3 miles away and when I go to leave it wouldn't start? So I pulled the line off and once again no fuel? Can the line be plugged from the tank? I know the tank was almost full, so I know it's not out of gas or anything? anyone got any ideas?