Larry - if your tank is at all salvageable get it "rebuilt", it's a lot of work to change the location - there's no repro available I've heard of, but alternatively you might have one the same shape made up of aluminum [at least there's a fabricator here that could do it] or check the wreckers for something that has the filler in a similar location, maybe a Blazer or Cherokee, that could be mounted the same
if you can't find a seat [I believe '47-'59 and some early years sedan delivery and school buses], consider the 60-40 seat from an '86 PU we put
in my buddies '56 for a replacement, it fits well and allows some access to the rear
for the rear sill, if you're not in a hurry you
might find one, but also be looking for a good bodyman that has a floor mount type frame straightening setup who could pull and massage it back to shape
Bill