power trac 422, and agco-allis 5660, ,1845 power trac Greenworks CRT 426
My 2000 model 422 dimensions measure about the same as yours. top 8" bottom 7" , 1 3/4 "distance between . Outside to outside 16 3/8" , inside to inside 15 5/8. Those are the only measurements I took , I just used a ruler and eyeballed the distances so they might be off a little.
Power-trac 422 2003 model and 428 January 2015 model
I just built and installed my new roll over linkage. A larger shaft and pipe was used. The old arms were used but had to be drilled for the larger pipe. Hope this one holds. Here are some pics.
October-November 2005 was when I replaced mine on a PT425.
Previous attempts didn't hold up; much larger pin and rollover have been fine ever since with even heavier use.