Turns out the problem was in the fuel pump I rebuilt. I purchased and installed an already rebuilt pump made in the USA. It flow tested at a full pint in less than 15 seconds. Well within the shop manual's required one pint within 30 seconds. 
Thank you everyone for your suggestions.
Jim Yergin

If you take the pump off, you could measure the eccentric stroke by measuring the distance from the pump mounting surface to the eccentric, turning the engine over to find the low and high points. I am not sure what the correct value would be, but someone here may know.

Any chance the actuating lever of this pump is incorrectly contoured as well?

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

Jim, did you operated the pump by hand before installing it. I do that with every pump I’ve ever put in. A bad one sounds different than a good one. Also can you look in the hole with a mirror and a light to see the eccentric? 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

Thanks for the responses.
The pump is an original AC pump that I rebuilt.
I don't think it can be a problem in the tank because it had the same low flow problem when drawing gas from an independent gas can.
Jim Yergin

Sounds like your tank pickup sock is plugged up a bit.   Hard for a vacuum pump to keep up, but the electric pump overpowers the clog.  Joe-JDC

JDC

Is your pump an off-shore aftermarket pump? There have many complaints regarding off-shore (China) fuel pumps. For that reason, Casco is paying $50 for rebuildable pumps made in USA and Mexico.

I think I would have to pull the front cover of the engine to get to it. I would rather not have to do that if possible, but good suggestion. My engine only has 60,000 original miles on it and when I refreshed it 10,000 miles ago I did not notice any wear on that part.
Jim Yergin

Can you measure the eccentric for wear. 

Thanks for the responses.
This has been a problem from the start with this pump. It was also a problem with the previous pump which is why I installed this rebuilt pump.
Jim Yergin

Is this a problem that has developed, or was it always a problem with this pump?

If there are no restrictions and the check valves are seating properly, the only other reason I can think of for insufficient volume would be insufficient pump stroke. Maybe the pump eccentric is worn out?

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive