Lee,
The Torque Tube 1/2 tons from 46-53.1 all had the same differential with the 4.11:1 gears.
To get lower gears without buying the kit from Patrick's or one of the other usual suspects, you will have to gank the drivetrain from the transmission back and replace it with something newer off of a later truck (or car).
If you are trying to keep your truck stock looking, I'd go for the gears, or keep the 4.11:1. You mentioned swapping the 216 out for a 235... That would let you go quite a bit faster, as you can wind the 235 out further without blowing it up.
Personally, I like being able to change the rotation of the Earth in first gear...
