Power steering adjustment???

I finally got the 67 Notch on the road with new tires, brakes, shocks ect. I notices a dead spot in the neutral steering position that allowed the car to wander a little bit. I tightend up the steering box adjustment jam nut & set screw which got rid of most of the problem but there is still a little bit of wander. Is there another hydraulic adjustment on the power steering to be had or is it a trip to the allignment shop. I am convinced it is in the steering and not allignment.
TIA-Rat