Steering Pittman Arm Question

[benw88]

Hi All.

I have an interesting situation going on with the steering on my truck. 1968 C10 Stepside. Originally a 6-cylinder truck but my dad and I dropped the 350 in back in high school. I converted the manual steering to power steering using a power steering box which I believe to be from a 73 and up C10. I think I left the steering linkage the same and used 73+ C10 tie rod ends, spindles, calipers, and rotors. I do not remember if the pitman arm is from the 68 manual set-up or from the 73+ C10 front end that was given to me.

Once I got the truck together it steered further to the left than the right

I was poor back then and had to leave it that way but now that it's been a few years I want to correct it.

I pulled the pitman arm from the gearbox and straightened out the tires with the truck in the air. I then went in the cab and determined the midpoint of the steering by turning it full lock to full lock without the steering linkage connected to determine the middle of the gearbox travel. I was then going to connect the pitman arm to the gearbox and straighten out my steering wheel but I was not able to do this because the gearbox is keyed so the pitman arm can only go on one way and that "one way" results in my steering turning further to the left than to the right.

My question:

If I open the box up can I rotate the keyed shaft so that my pitman arm lines up or at least close enough to use the tie rod ends to make the final adjustment?

What Gearbox do I have and is it even correct? (want to buy a new one anyway because of the leaking)

Is the Pitman arm the problem?

Thanks a lot for reading my novel!