I know this is a very old post, but I was reading it for suggestions. I replaced the fuel lines and gas tank on my 1954 truck. I see some very creative solutions regarding priming the line but custom solutions with pressuring the gas tank started making me have flashbacks to the Red Green Show. So, I went with the simplest approach I could think of and let gravity do the work. Before I connected the line to the gas tank sending unit, I attached a small funnel using a short rubber hose to the fuel line fitting. I then added some gas, and loosened up the the fitting on that same line at the fuel pump end, just until a little bit of gas came out. Knowing that the line was now full of gas, I removed the funnel and attached the line to the fuel tank sending unit.
I did the same thing on the line going from the fuel pump to the carb. With both lines full of fuel, my truck started up after about 4 seconds.
Hope that helps any new comers to the thread.
