OK, I'm still a bit confused- - - -you're running the original straight axle with a rack & pinion mounted to the frame or body? That's a recipie for disaster, and it should be illegal to drive a vehicle set up that way. The only possibility that's even remotely capable of succeeding is one where the rack assembly is bracketed directly to the axle, and there's some sort of sliding coupling such as a double D shaft connecting the steering column to the pinion gear. Even with that setup, they're notorious for binding up and basically locking the steering at unpredictable moments.
If you're planning to keep the rack and pinion steering, the only safe, relatively simple setup will be to swap to some sort of independent front suspension. R&P on a straight axle is a deadly accident looking for a place to happen and its criminally insane to put one like that on the street!
Jerry
