Copper lines on cars/trucks has been discussed quite a lot. I know most say, "Don't do it."
With that in mind............ my buddy used copper to run the fuel line from the tank to the fuel pump on my 150 Wagon I bought from him 18 years ago.
I know for a fact this copper fuel line has been on my Wagon for over 20 years now. So maybe it's not the smartest thing to do but it can work.