Steering All Over the Place at 55mph+

67Dart273 said
If you are good at fabrication you can also rework the 67 K to take a 68/ later idler, but you damn near need a 68/ later for a pattern

So far as the wander, I'd get a pal and start from the top and work carefully down. Do not assume ANYTHING, and especially just because 'it was replaced.' Have a pal wiggle the play in the wheel while you look. Look everyplace there is a bolt, component, bearing, shaft, coupling, tie rod end, coupling or ball joint. Look for unwanted play and movement in everything that is supposed to move, and unwanted movement in everything that is NOT supposed to move. Bear in mind you might have a rusted/ weak/ cracked frame horn, K member, or the steering box loose on it's mounting bolts.

So far as alignment, you can do that yourself with very little special equipment.

That wiggle the steering wheel to check for wear in the steering column and box can be a difficult to explain to some people. What is frequently done is said helper grabs the steering wheel and gives a healthy pull past where resistance is felt. What is required is index finger and thumb only and just move until resistance is felt. Then move back the other way. This just moves where any wear or slop is. The same pertains to watching for wear in tierod ends, pitman arm and idler arm. A worn idler pivot will.move up and down and can generally be felt by pushing up and down on the joint to the tierod.