I need help ID'ing the pitman arm currently on my 70 Cuda 340, Power Steering. The arm has what looks like part% 2835378 on it and NOT 2835880 which my parts book shows as oem. I'm hoping this is from a later box using the less expensive pitman arm. I know there is a differnce with shaft size or such, but don't know for sutre how to tell. Can anyone run the part I have on now, and advise me as to which replacement I need.

Thanks