The steering box has a positive center position. When in this position, the worm and peg should have just a little bit of drag. When you move either side of center, there is noticeable play, even with a brand new and properly adjusted box. Here is the order you must assemble the steering:
1) with the steering linkage disconnected from the steering box pitman arm, turn the steering from lock to lock and count the number of turns. Then, starting from one lock, turn 1/2 the total to bring the gear to center.
2) Your steering wheel MUST be centered at this point. I still do not mount the steering wheel yet, but if it is mounted already, make sure that it is centered.
3) Gently rock the steering back and forth over center and you should feel a point, right at center, where there is noticeable drag. If you are turning the steering shaft by hand and without the wheel, it should be very noticeable. If you have the steering wheel installed, the wheel leverage will make it barely perceptible. If it is tooo much or not noticeable, then unlock the adjuster on the steering box and adjust until you get the slight drag as you rock back and forth past center.
4) Now, install the steering wheel at the exact center. Then install the trafficator so it cancels at the same number of turns left or right. Installing the trafficator usually takes a couple or three tries to get it centered.
5) Once all the above has been done, you can re-connect the steering link to the gear pitman arm.
6) Loosen the steering tie rod sleeve adjusters on both sides of the car.
7) Lower the car onto its own suspension and on a flat section of pavement. Rock the car back a few feet, and then forward to a stop while keeping the steering wheel perfectly centered...best to have someone in the drivers seat so it doesn't roll away down the driveway!
8) When you push the car forward, note which way it goes with the steering wheel held centered. Turn the tie rod adjuster sleeves an equal number of turns to bring the front wheels in the direction you need the car to go to straighten out. Also, step about 10 feet in front of the car and bend down so you can sight the front tire on each side to its rear tire. The left and right tires should sight to align up with the rear tires, or only just noticeably line up just outside the rear tires. This is to ensure your toe is not out.
8a) to clarify step 8, picture if you have a helper hold a straight edge horizontally against your front tire, about 6" above the ground. Then, you stand in front of the straight edge and site down it to where the site line meets the road at the rear tire contact spot. That site spot should be from on the outer edge of the rear tire to no more than 1/2" outboard of the rear tire. That will give you 0 to 1/2degree toe in.
9) repeat steps 7 and 8 until your car tracks straight. As you get close, you may need to take a short drive to make sure it tracks perfectly straight with no toe out to very slight toe in.
10) tighten your tie rod adjuster sleeves.
11) Jack your front end up again and set your lock stops behind the trunnions for the most travel of the steering without any parts contacting each other.
That's the order that must be followed to get a superb driving TR. If you jump ahead anywhere, then you must go back, as all later steps affect the earlier steps. Best of luck...