[Mart]

Nige, do you have the original spindles or 37 up spindles and a bolt on arm? (As glennpm is alluding to). The original steering arm sticks forward. If you have a bolt on steering arm the stock drag link is no longer the right length.

You need to attack this from first principles.
Disconnect the drag link.
Check the toe-in and set the wheels straight ahead.
Find dead centre on the steering box by going from one lock to the other and stopping half way. Make sure the adjustment is right and the sweet spot is right there in that position.
Questions: Where is the keyway when in that sweet spot/straight ahead position? Does it make sense? Will the steering wheel be aligned correctly in that position?

Now see if the drag link will just drop into place. In theory it should do. Chances are it won't.

You now face having to get/make an adjustable drag link, or getting lucky if clocking the pitman arm one spline (after filing out the dead splines) puts it right.

If the box is in the straight ahead and the wheels are straight ahead and your steering wheel not aligned, then you have a few options.

Modify the shaft with a second keyway in the right place.
Modify the steering wheel with a second keyway in the right place.
Cut the steering shaft, align it correctly and weld it back together again.

It all depends on how handy you are feeling.

Mart.