If you are going to replace your Saginaw Power Steering box, then you need to look into Power Steering Services. I had the 12.7:1 Fast Ratio Steering Gearbox Conversions processed on my steering box and wow, what a difference. Note, I have not driven the mustang with the box, but I can tell a difference in the turning during installation vs. my old box. Now, it took a few weeks to get it back.
I too have this "wandering" deal going on with my car. The steering box looked new when I got it, and I have made some minor adjustments with it, but it still likes to shift slightly every once in a while. All steering components are new, should I just have the steering box rebuilt again anyways?
Grab somebody and check the system from steering wheel to tires. Have your helper rock the steering wheel back and forth and look at the rag joint, then watch the steering box's input shaft vs. the pitman arm, then check the tie rod linkage then the wheel bearings. You would be surprised how easy it is to spot worn parts this way, isolated with good light...
New box is in. They sent me a 3 turn lock to lock quick ratio even though the part number was the laze 4 turn box, yee haw. I bought a pitman arm from Mustangsunlimiteds website for $34. Night and day difference. Its a pleasure to drive
On my mach 1 it was a full time job driving it down the highway at 55-60 mph... so I replace the steering box and wow its drives great now.. No wondering from ditch to ditch... I bought mine off of e-bay for like 150 bucks and it is a power steering car.. now if you have a 351C with headers it a very very tight fit and a pile of work but so worth it....
Ive been looking for a box for a few months, ended up ordering from rockauto when one popped up, was pretty cheap. Mine is a power steering car as well. My old PS (and POS as well lol) just cleared the header, but the new box rests right on it, and the vibration is awful, have to work on that during the week.
Where in Nebraska are you? I bought my car in Omaha 3 years ago and dragged it home