I used the steel lines (3/8 supply, 5/16 return) for my EFI setup. Works great on a healthy 496 with tank in pump. I used short lengths of SS braided line at the tank and engine ends to make the connections.

With EFI, you need pump in tank or a sump to get decent pump life and ability to use all fuel tank capacity. EFI pumps do not like to suck.