Manual steering box with 35 spline

It should be a 5/8"-36 spline all the boxes from 62-up used this spline.

There are several different spline sizes with in the 5/8"-36 size. 600", 605", and .620" on the major diameter, but a Mopar takes one with the .620" major

outside diameter. This is the same size a Stiletto rack uses.

I have never seen one that was a 1/2", so if it really is you got something odd there.

Tom