84 D150 power steering conv.
 

Converting my 84 D150 from manual to power steering. Last part to install is pitman arm and my old one is a smaller diameter spline. Every listing I have found so far is for the same part number I have. Is there a difference between manual And power steering pitman arms? Did they upgrade to a larger splined shaft in the steering gear box?

1.250 For the Power Steering output shaft
1.120 For the Manual Steering output shaft

You might need a different steering column for conversion but im not sure.