[G.M.]

Copper work hardens and cracks after a LONG time movement of a short area. On a typical old Ford there should be no unsupported section that would be subject to movement. The only place this occurs is from the firewall to the fuel pump. This is the job of the hose to take the movement out of the solid fuel line. I'm not promoting copper line and have some on a few of my old Fords but it's not a problem. If steel is available for the main fuel line that is best. From the pump to the carb, the proper length has no flex motion. G.M.