1964 Dart manual steering pitman arm shaft seal.

I found the below links useful when I rebuilt the manual steering gear in my 1964 Valiant. I even bought one ball bearings from an out-of-state Chrysler dealer, last one in the country shown in the system.
www.forabodiesonly.com/mopar/threads/my-manual-steering-box-rebuild-w-valid-part-numbers.36427/
www.moparts.org/Tech/Archive/steering/3.html

I recall using a sector shaft seal from a power steering kit, but it has been a while. If that works, those can be bought cheaply alone at rockauto.