Looking for either rust free (has a metal filler tube inside), or NOS. My aux tank has developed rust through in the metal neck inside the plastic tank. It's been garaged for close to twelve years (with occasional drives, but that's all), and I guess condensation caused this. The metal part appears to be molded inside the plastic tank. I am not 100% sure, but it appears that way. I have a good plastic tank, and a spare from a '77. What I found is on the '77 tank the restrictor is recessed further down in the tube; the '78 is up just inside, under the cap. Thanks for any help or leads.