Changing fuel tank in a 1968 to a plastic rally tank

Hey Everyone. Have e 68 T that I want to future proof as much as I can while I have the trans ad engine out. this involves changing fuel lines to ethanol resistant lines and changing out the old metal fuel tank to a plastic one. Bought a Porsche 80L (?) version, and apart from going form a full size spare to a space saving one, I think it's fantastic.?
The issue is, I believe in the exit and return lines hook up differently than my 68. Anyone done this take change to an earlier car? photos? tips?

Your 68 only has one line to the engine. No return. Since that is a metal line thru the tunnel I see no need to replace it.