63-72 idler and pitman studs point towards the hood. (Nuts on top)
73-76 studs point towards the ground. (Nuts on bottom)
Idler and pitman arms must be mated to the same era center link. All 67-72 or all 73-76. The tierod assemblies are all the same.
I have a 73 style K and discs in my 68 but retained the complete 68 steering linkage. Seems to work just fine. One or the other style may be better when it comes to header clearance.