If it's a stocker you don't NEED to replace them, but new bars are a performance upgrade. The largest original T-bars are small compared to replacement bars. You don't need to get crazy big, maybe an inch; This will increase your road feel, especially if you do some steering upgrades and have modern tires. The original bias ply worked, but your not running those are you? I recommend upgrading the bars, and all the bushings, and welding reinforcing plates on lower the control arms ; along with shocks, ball joints etc... This will also highlight any weakness or sagging rear springs.
From Hot Rod Mag "
In a Mopar front suspension, the lower control arms are like heavy equipment on a job site. They transfer all the torsion bar's force and actually hold the car up, while the strut rods handle the fore and aft forces. The upper control arms locate the uprights and swing along for the ride. When Mopars are equipped with a sway bar--you guessed it--they tie into the lower control arms. If performance handling is the goal,the lower control arms had better be in top condition".
LCA plates, only $20 :
http://arengineering.com/product-page/lca-plates/
Here is a Mopar Action article "Pump it down." it is an easy
no cost mod to your power steering pump. I did this mod too, and can recommend it:
http://www.moparaction.com/tech/beep/PUMP_IT_DOWN-re-v1.4.pdf