It will work as long as he takes all the steering gear including the box. The idler arm mount on the k frame is the same from 68-76, ditto for the steering box location.
Theres differences in the center link and the steering sector shaft diameter that will not allow mix n match of the steering components between the years, but the "complete" steering assembly from a 73-76 car will bolt in and work fine on a 68-72 k frame.
