Steering boxes, diffence in years or 1/2 - 3/4 ton?

[northerngmc]

Is there a difference in manual steering boxes between 67 - 72?

Is there a difference between 1/2 ton and 3/4 ton?

I believe the box in my 69 GMC 1/2 ton is well worn, but both the boxes in my 70 GMC 3/4 ton and 72 GMC 1/2 ton parts trucks have less play. I am considering swapping one of them into my 69 GMC 1/2 ton.

I did a little research this afternoon on here and I have already adjusted the box in my 69 1/2 ton by turning the screw in on top, but it is now all the way in. I started with about 3/8 of a turn of the wheel in play and now I am down to 1/4 of a turn. I also checked my front steering and everything seems fairly tight and clean, maybe the PO did some work on it? I also tried turing the steering column under the hood and the play appears to be in the box and the arm on the bottom does not move when I trun the column shaft back and forth.