Marty you make me sound Like I plan ahead!
I've got a std underfloor tank that came with the van which looks pretty ok, having been powdercoated.
As to the sender,etc etc, who knows.
I'm not precious on this van about being original, for $140 with new pump and sender that would be fine by me, so long as it's not an issue come rego time.
I do have an idea in my mind though of rolling a new rear valance, and having a single centre oval shaped exhaust tip, Boxster style. I havent got to figuring how a pinto exhaust needs routing and if there are any issues with diff/underfloor tank etc.
Can you post link if you buy, happy to tag along.
If you need measurements of current tank, I can take happy snaps and measure tonight.