So if you have a fuel injected car and its a V8 you have the following:
Fuel Rails (steel and hold the injectors)
Fuel Rail to Body Lines (steel and one has a Schrader valve on it)
Body Lines (steel at fuel tank to just past the passenger front control arm then transitions to flexible)
Body Lines to Fuel Tank (flexible)
Just need to know which one(s) you are wanting to replace and what year car and which motor is in it and if you are carbed or injected. My guess is the Body Lines but its just a guess.
I would say for ease of installation on an injected motor and if you are not wanting to go back stock I would go with Teflon lined braided AN6 lines. You can get the adapters that fit the fuel rails and have female AN6 connections. You can also get the adapters that will connect to the factory fuel pump hanger to provide female AN6 connections at that location. If you want to keep the factory style fuel filter then all you need is two more of the adapters for the fuel pump hanger to pop on stock filter and then make up your lines from tank to filter, filter to fuel rail, and tank to fuel rail (return).