727 beginner question/verification

Offer it as a straight up trade on a small block trans. Also could just sell that big block trans outright and buy a small block version.
Since it's not a numbers matching deal, you can even get a small block 727 from a non-four wheel drive truck all way into the early 90s model years. The tail housing was shaped a little different but still uses the same mount in the rear and has the same length. Just stay away from the really short version in campers and some vans and heavy duty trucks. They are great for parts donors, but the stubby tailshaft setup isn't way to go go in the rear wheel drive cars.