I'd like to fab a custom pitman arm with replaceable ball joints. For ball joints I was thinking about using uppers as they have the same taper (7 degree) as the pitman arm. Question is if the shank diameter of the small A-body ball joints or the larger ball joints is correct for the drag link (what is the thread of the pitman arm, idler arm, tie rod nuts? Can't remember if it was 7/16, 1/2 or 9/16)?
What is the outside diameter of the small upper ball joints (I need to source the correct screw in sleeve)?
Has anyone done something like this before and wants to share his experience?

In case anyone is wondering: I have an Isuzu box in front of me and they have a very odd sector shaft spline count (40 splines or 36+4 blanks). I could weld the spline part of the Isuzu arm to a Mopar arm but this would mean I have to do it again every time I need to replace the pitman arm.