68 Charger steering issue

The shops that rebuild OEM steering boxes do VARY in quality.
Firm Feel and Steer and Gear offer options to increase the steering feel and cut down on the overboosted sensation. Other vendors often just disassemble, clean and reassemble the units with no regard for addressing the loose tolerances. Lares and Cardone are two vendors that just clean and regasket. If the box was loose before, it will be loose afterwards.
It could be a matter of a bad idler arm, loose tie rod ends or overall poor alignment as well.