confused, steering gear compatibility

The whole deal with later/ early boxes (big/ small pitman shaft) is the center link, pitman and idler. Everything else fits. I guess the exception is the 67 K member which has a "different" idler mount, so I'm not sure there is any way to adapt a later idler to a 67 K, at least without fabrication/ welding, which at least one member on here did.

So look at your center link where the studs come up through for the idler and the pitman. Are the nuts that hold them on top or on the bottom of the center link?

Early setup has nuts on top:



Late linkage has nuts on bottom: