Calling everyone that has a car with a 73 up style K-frame!

I am really considering swapping to the 73+ spool mount type k-frame and sway bar if it really is that much narrower!!

Also, I can use the same lower control arms correct? There will be no differences at all? What I dont understand is, how can the sway bar be narrower, (on the newer k frame)
when it has to mount to the same location??? (mounts to the same spot on my lower control arms)