My 67 Dart has a electric fuel pump, it runs, but will not pump fuel to carb.

The car just died going down the road. No fuel getting to carb. I disconnected fuel line just after fuel pump to see if fuel would come out. The pump ran but no gas was flowing.I ended up filling gas tank right to the top and all of a sudden gas came pouring out.I reconnected fuel line and car started right up. At this point I just let the car idle for a while next day car started up again. Fast forward two days later, I needed to put a new fuel sending unit in, drained the tank put new unit in, put about three gallons of gas in, fuel Gage now works, but car is again not getting fuel to carb. Fuel pump is running but no fuel is coming out. Is it possible that fuel pump needs replacing? But why would pump run and not send fuel. Any help would be great. Thanks.