Tie rods and drag link are adjustable for play on the AD. If there's play, try pulling the cotter pins in the ends of the loose part,then turn the plug in. You'll need a drag link socket (looks like a big screwdriver bit) to do this. Once you get the slop out, turn to the closest hole in the housing and install a new pin. If it's in the box itself (very possible) then the lash needs to be set in it. On the engine side of the steering box, there's a slotted adjuster screw with a locking nut. It's very similar to the lash adjuster on the rocker arms. Take the nut loose, then turn the screw in, periodically checking the feel. Ideally, you would check this with the drag link disconnected using a scale, but going by feel works fine. You want to have as little play as possible, which should be easy to get with a NOS box.
You wil want to have the alignment checked, especially toe-in if you hae to mess with the tie rods. Stuart's got the right idea on the other angles, jsut has the wrong one. Caster is the one you'll want to have checked. Camber is non-adjustable on the I beam trucks without bending the axle, but caster can be corrected with shims under the springs. caster is also more critical to straight ahead driving- more positive caster=more stability, but harder steering. negative caster=easier steering, but less stability.
