If you plan on keeping the original steering column & wheel(which I would) you need:
1) a power steering gearbox
2) a pump w/mounting bracket & hoses
Depending on the gearbox,you may need to change the lower steering shaft end &/or the pitman arm to fit the box. Some GM boxes match the standard Jeep pitman arm,but the Jeep box uses a different pitman arm for manual or power steering. It's been a while since I did mine,but that's all I can think of right now. Hope that helps....let us know how it goes!
