I finally located the 5/8 ID fuel hose at a boat shop. I inserted a %/* diameter spring that was six inches long and the hose bens well and maintains its shape.

AlS

I just did this job on my 72 Z and got all the fuel lines from NAPA auto parts and got a six inch spring that fit snugly in the 5/8 line and have not had a problem since with fuel vapors in my car but I still can't fill my tank more than 10 gallons so I am thinking that one of the vent outlets on the tank is plugged:angry:

I just replaced mine. The factory-formed walking-stick shaped hose wasn't available in Australia so I got a piece of copper tubing in a slightly smaller gauge than the fuel hose and waited outside a plumbers merchants. After a couple of minutes a plumber turned up in his van so I got him to bend the copper tubing into the bend (a U-shape). I then got a couple of pieces of the right gauge fuel hose, connecting it (via jubilee clips) to the ends of the copper pipe.

It works fine and I haven't noticed any problems with it, I can also fill my tank right up with no problems.

I had to drop the fuel tank to do it, but it really is an easy job and doesn't take that long.

I did have to go to a specialist "hose" shop to get the fuel hose though..