I bought a new tank and sending unit also. I was going to re-use the old filler neck tube, because it looked very good from the outside. But when I got it out, it was very badly rusted on the inside where it sits down in the tank. I ended up replacing the tube also.
BTW, I did buy a Spectra tank. Many people on this site recommended them.
Thank you much for your help! Did you go with a vented tank and cap, Did you use the spectra sending unit also and did you have any leak issues. Just trying to get it right the first time. Mike
