Just to do a wrap up of all that's been said and make it all correct: All A bodies after 66 use the same center (drag) link on 6's and 8's. The 73 and up used a DIFFERENT centerlink than the 67-72. The POWER STEERING box on a 73 and up used a different clocking (gear pattern at the bottom of the box) meaning that the pitman arm from a 67-72 will not fit the 73-76 power steering box. All steering boxes will bolt up to the K frame from 67-76.
When you switch to the newer spool k frame you have two options: Run ALL the 67-72 steering parts (drag link, pitman and idler arms and STEERING BOX) OR run ALL of the 73-76 parts. Either setup will bolt to the k frame but when you start mixing and matching parts, you'll have problems.
