new to forum, have rear end question

Let me start by welcoming you to the forum.
And yes that subject has been talked about numerous times.
It depends by what you mean by economical...
I would recommend staying with an "A" body unit, therefore no modifications required for axle lengths and leaf spring relocations (can get $).

An 8 1/4" unit are still quite available at a reasonable price, and can take some abuse.

What rear do you have in it now?

All the best.