65 C10 power steering help please.

[trip55]

Hi, I live in England and own a 65 C10 panel truck .
Some time in its life it has been converted to power steering using the 67 up Saginaw p/s box.
When I purchased the truck a couple of years ago I noticed that it had a much tighter turning radius turning left than turning right.
I recently had to have the steering box rebuilt and when the guy at the garage removed it he found that there were no strengthening plates and an assortment of washers used to mount it for clearance. He fabricated the necessary plates and spacers, a great job.
Unfortunately I now have a reversal of the turning radius issue, tight right and much less left.
I believe that the pitman arm can only be fitted in one position as that was my first thought.
Just wondered if anyone has encountered this problem before or if any of you guys out there have the solution as making left turn can be a bit embarrassing sometimes.

Sorry if this has been covered before.

Any help is much appreciated. Thanks