I'm getting a jarring feel through the steering wheel. I've looked for play in the front end, but everything seems tight. I've had aligned and replaced the struts and shocks. The rack is the only thing I haven't looked at. Should I just buy one from AutoZone, or order from somewhere else?
If your rack is OE the best suggestion would be to have that rack rebuilt. The rebuilt parts store racks are okay in terms of durability, but they will almost all have a very light feeling (imagine a lincoln town car steering) that is not sporting and gives very little feedback from the tires.
An Autozone rack will probably do you fine, but you could always check out places like CJ Pony Parts, Latemodel Restoration, American Muscle, etc for an OE replacement rack
I used an Autozone rack (Duralast brand/rebuilt) in one that I had that was leaking and it worked fine. Before I got that rack I went through 3 of Advanced auto's rebuilt racks from some company that I never heard of and the first had the inner tierods backwards, the second blew its input seal in about 50 miles and the third had the tierods backwards again. I am done with Advanced auto's "rebuilt" parts.