-64 A body manual steering box

All manual steering boxes have the same output(sector) shaft size, unless they are from a C-body or a van. The only difference in pre 67 boxes is the mounting holes are smaller than the later steering boxes. (7/16” vs 1/2”) They will interchange if you don’t mind having a slightly larger mounting hole on your early K-frame. (You shouldn’t mind, ain’t no big deal)