Possible to install 1971 upper ball joints in 1974 control arms?

[D-n-Tyke]

I am trying to figure out if I can make this work. Have a 1974 C10 full front suspension. I also have a set of 1971 C10 drop spindles I would like to run. So my question is, I believe the lower ball joints are the same between the 1971 and 1974 (.855"), but I think the tops are different, 1971 (.682") 1974 (.716"). Can I just replace the 1974 ball joint with a 1971 ball joint? Will a 1971 ball joint bolt into a 1974 control arm?

Are there other issues I might have? Will using a 1971 spindle with the 1974 tierods work or are those different also?