I do not know if they make them for A-bodies yet. I've only seen them for B/E-Bodies so far.

I did the same thing, with a Rockauto Coupon I got my 71 Challenger EFI tank for just over $200.

https://www.rockauto.com/en/catalog/dodge,1971,challenger,7.2l+440cid+v8,1496987,fuel+&+air,fuel+tank+&+pump+assembly,17130

There is this intank A-body tank with pump.

http://www.tanksinc.com/index.cfm/page/p...prod/prd481.htm

And intank is always better then outside, helps keep the pump cool and lasts longer.