Pitman Arm ID - 70 Cuda

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

2835878 is the casting number. It is the correct one (part #2835880) for your car. Casting numbers are very often different from the part number by 1 or 2 digits.

BLESS YOU. How the heck do you know which is the casting number and which is the part number. The ONLY number I can see on this is the 2835878 number. Now I know which to order. THANKS AGAIN