Maybe the pick-up sock plugged? Filter in the carb inlet plugged? Needle valve stuck closed? Did you disconnect the fuel line at the carb and crank the engine to check if the pump was getting fuel to the inlet? I recently had a quadrajet that was getting no fuel, I suspected the pump but when I disconnected the carb inlet line and cranked the starter [coil wire off] the pump worked well. It was a stuck needle-seat.
