Unless you've mixed up the track bar and drag link terms or the track bar is bent, you adjust the length of the drag link via its short length adjustment sleeve to straighten the steering wheel.
Find the drag link in the below photo, which is connected to the steering box's Pitman Arm, then locate the short sleeve clamped in place onto it with two bolts. Loosen those two bolts and with a big set of pliers, rotate that sleeve until the steering wheel is centered.
If the steering wheel is rotated too far to the right when you are driving straight ahead, that means the drag link is a bit too short and needs to be lengthened. Visa-versa if the steering wheel is rotated too far to the left.