I just changed the pump on my '75. It shares the same mounting location as yours. It's a vane-style pump so you will hear the vanes rattling in their grooves if the pump is full of air. As mentioned above, I used a rag to seal the fuel filler and stuck an air-gun attached to my compressor to push fuel back down to the fuel pump. Worked beautifully.
Sadly something else failed two weeks later sidelining the car again...
