1948 Plymouth fuel tank line fitting does the doubble flair seat against pick up tube or is there a special fitting?

On a 1948 Plymouth, the fuel tank line fitting uses a double flare that seats against a brass fitting on the fuel tank's pickup tube. There isn't a special fitting beyond the standard double flare for the fuel line itself; the brass fitting in the tank is the mating part. However, the condition of both the brass fitting *and* the flare on the fuel line is critical for a proper seal. If leaks occur, you'll likely need to check and possibly replace one or both.