Front suspension set up

Try the tires first. Radial and bias tires on the same vehicle can cause some really funky handling, especially if the suspension has some slop.

If it were me, I'd replace all of the bushings, tie rod ends, idler and pitman arms with OEM grade parts before replacing the steering box (unless you are converting from power). Also, I'm not knocking the Wilwood brakes, but the cost would put them pretty far down my list.