K frame confusion
You can use any K from 68--76 with any other parts (67 had the oddball 1 year idler arm to K mount)
You can use lower arms from 67/ up depending on if or what you need for the anti roll bar tabs
You can use the center steering link from 67--72 or the steering link from 73--76 as long as on EITHER center link, you match the appropriate idler arm, pitman, and of course steering box splines.
To repeat, your problem has NOTHING to do with what the K is actually out of. Be aware that as old as these girls are, it is very possible that the center link and other parts were already swapped onto the K that you have
One last time, the CENTER STEERING LINK is the KEY to your problem. FOUR parts must match. Center link, idler, pitman, and steering box splines