Fuel Pump vent holes leaking gas

[tattooboy37]

63 c20 w/ 283 . I recently noticed gas leaking from what appears to be vent holes on the upper part of the fuel pump. I've been having a loss of fuel under heavier throttle unless I ease into it. It has been driving me nuts because I recently rebuilt the carb. put in a new inline fuel filter ect. I've been chasing the carb for the last couple weeks and am pissed at myself if its the damn pump all along. In the course of the project I remember cleaning all the built up crud from the fuel pump while installing the new lines. Could the holes have been plugged before and not allowed fuel to escape? If my friend puts his fingers over the holes and I work the throttle it doesn't seem to want to sputter. if he removes his fingers and I open it up you can tell the air/fuel mix is off and it wants to die. at idle it is leaking just a little and when the throttle is opened up it seems to suck air and not be delivering enough fuel.
Is the pump shot or do/can those vent holes be plugged. the replacement ones online appear to have a recessed spot like a hole, but it looks plugged up. Is that vent necessary cause everything is perfect when my friend blocked them w/ his fingers.