Steve is correct but that's really only an issue at Bonneville or maybe the Silver State Open road races where you're at full throttle for many minutes at a time (in any gear). Then the engine may go lean and burn valves.
As I remember, the late fuel gauge sender with external fuel feed is a bolt-on but uses the same (metric size) 5/16" OD fuel line. In the past I welded up a few of these substituting 3/8" OD U.S. steel tubing. You need the old sender parts to do this so don't s-can an inop' one.
When adding the late sender in early cars, the rust-prone welded tank line can be used as a fuel return for EFI systems even if perforated. Or just cap it.