I have to agree, I don't think it's a tank or pick-up problem, the sock pretty much touches the bottom of the tank and unless you are very low on fuel and tipped to one side it should be able to supply fuel. I would be looking at the pump and carb.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy