Here's some interesting Steering Box info I found:
Mopar gearboxes from 1966-'74 only came in two ratios: The manual steering gearbox was a 24.0:1 ratio with a radius of five and a third turns of the wheel, while the power steering boxes came in 15.7:1 and three and a half turns of the wheel. Manual gearboxes can be adapted to a quicker 20.0:1 ratio with the purchase of an aftermarket worm gear and shaft assembly from Mopar Performance parts (part number 4007612). Gearbox rebuilders can also install this unit for you.
The only Mopars with a quicker ratio gearbox were the 1970-'71 AAR and T/A models, but your chances of finding a unit in a salvage yard for these cars is almost zero. Using the conventional 15.7:1 ratio power steering box with an extended Pitman arm and idler arm can provide a similar effect in the handling. Although the T/A or AAR Pitman will not fit the common gearboxes, you can get extended length components from aftermarket supplier Firm Feel Suspension. These are available for all popular A-, B-, C-, E- and F-bodies. The added length, effectively adds to the response of the steering system, serving roughly the same purpose as modifying your existing gearbox or browsing through the salvage yard for the quicker steering unit. Dart and Valiant A-bodies from 1964-'72 would require changing to a later 1973-'76 A-body center link, as well as the longer Pitman and idler arms to maintain the proper steering geometry.
