Keep in mind that it's actually easy to center the axle during a track bar installation and during that process, the track bar has nothing to do with centering it.
The axle will tend to self-center itself just via the action of the springs and control arms. If it's not perfect you can use your hands to push the tub over a tad or jump up & down on the bumper until the axle is acceptably centered. Then the track bar's length is simply adjusted so its bolt holes match up to its two mounts and you bolt it in, no muss no fuss.
This is a true fact, I spent so much time trying to center my front axle. I used a porta power, and kept ended up making it worse, then @Jerry Bransford advised me on this, and sure enough disconnected the front, and drove it back and forth; jumped off of the bumper, and then measured and sure enough dead center, well quarter of an inch off, but closer than when I man handled it. I had to adjust the bar a lot from where I thought it was perfect till where it self centered. I was so far I off, I am wondering if I was drunk at the time.
Anyway this is excellent advice, and it really works!
