1966 dart power steering info

Saginaw pumps were used on 273 etc... Both my 67 273s wear saginaw pumps.
I don't know how different the earlier saginaw pump might be from the one you have. The brackets would likely be different for the cast iron water pump. Brackets you have would have been on later aluminum water pump. Pulley offset may be different also. 273 p/s belt runs in front of the alternator water pump belt.
About the pitman arm... where the size of shaft changes the up/down direction of the ball stud to center link changed. Unless some aftermarket vendor produces a bastard pitman arm, aint no way to attach this steering gear to your center link.