A roller idler arm will help ease steering, even with power steering (I paid ~$30 on ebay for a new one from Moog). You can get roller conversions from opentrackerracing.com, too. Also, a steering box rebuild from stangersite.com will renew your box (for less than $200), or you could get a replacement box from a Flaming River vendor for $400-500. Make sure there is no binding in the steering linkage, either. Finally, a good performance alignment with 2-3° positive castor, 0-1° negative camber and 1/8" toe will help stabilize the steering make the car track better. Tire size and ratio will make a difference--do you have the stock replacement (for the original bias ply) 14" radial tires or have you upgraded to 15+ inch wheels with better aspect ratio? Change the stock steering wheel for a more modern one for better feel, too.
Do you have manual steering? Does the car wander at speed? What do you expect when you say "stabilize" and "improve my steering"? Are you looking for a more modern type driving experience like a rack and pinion can help give?
If you are doing a disc conversion that involves replacing the spindle (like the discswap.com one or actual used ranada setup), wait to get the alignment done...