I just went through this process after rebuilding my rack and pinion. Here's the sequence I used:
- Center the rack (like Dpmulvan describes). I checked the centering by marking the top of the centered shaft and rotating to full lock on each side - the end points for the mark should be symmetrical, e.g. at 5:00 and 7:00. I did this with both tie rods disconnected so the rack could travel freely in both directions to full lock. On my '83, it is almost 3 turns lock to lock.
- Without disturbing the rack, remove/reinstall the steering wheel to center it (it probably helps to have previously removed the wheel and lightly fitted it so you don't disturb the rack position). This is so everything is centered when driving straight ahead.
- Secure the steering wheel so it doesn't move from the straight-ahead position, then connect the tie rods and adjust them to the desired toe. You can rough it in with toe plates (measuring the difference between the side-to-side distance at the front of the tires and the rear of the tires). I followed up with a Smart Strings type setup so I could measure toe separately on each tire to keep everything centered.
Good luck