Self-centering (or lack thereof) in park and camber / caster / toe settings

Raise the front wheels off the ground, loosen the two bolts that hold the valve block to the top of the steering box... They should be snug but not tight... Start the car.. Tap the valve block with a small hammer, forward or rearward... As soon as it moves you'll see the effect & you'll know what direction it needs to go.... When you get it close enough that the wheel stays where you put it shut the engine off then re-start it while watching the wheel... If it remains still snug the bolts, your done... If the wheel "kicks" you need to make a slight adjustment till it doesn't "kick" on start up....