The steering is never going to feel like a modern rack steering system, you can maximize it, but it is a systematic thing. So you need to check EVERYTHING one after the other and optimize it. Only check with a load on the tires- on the ground or an alignment rack. The steering column bearings, the coupler, correctly adjust the box, make sure the box is properly tightened, watch the box for k-member flex, it's very common. Make sure the steering arms are tight, wheel bearings properly adjusted and then suspension- i.e. ball joints and bushings are tight.___
The torsion bars and rear springs look like a good match.
You need to get a good professional alignment, have the car checked on a frame rack and have the rear checked for squareness. The factory tolerances are really pathetic on the frame and needing shims to square up the rear end is common- you'll note that several companies make them for old Mopars. ___
After all this, you can play with the shock adjustments.___

If you are O.K. with the body roll after all this, you are golden, if not I'd go with Firm Feel or Helwig bars. This is just my personal preference, Hotchkis and PST both make good product as well.___

The tires will then be the limit and those old T/As just won't get it done.