All non-OEM fuel lines must be metallic or steel-braided. A maximum 12 inches of nonmetallic sheathed-rubber line can be used for connection purposes only. To ensure we were within the rules, we first cut a piece of fuel line 12 inches long to make our connections at the fuel filter, fuel pump, and gas tank. In the June '03 article "Sneaky Shooter" we showed how we upgraded our fuel system. We didn't use the entire 12 inches of rubber line.