I don't recall having any problems installing power steering in my 68 before the body lift. The only problem I can think of is the radiator hitting the steering box. I ended up taking a hammer to the side of my radiator and pushing it in alittle, then re-brazing the small hole i put it in. the steering column shaft will have to be shortened a few inch's. In fact if I had it to do over again I would cut the shaft 4" from the bottom of the column housing and install another ujoint there as well as the one that should come with your PS kit. I would also put a slip shaft between the ujoints, that way if the body flexs it won't bind up the steering any, as mine did. I used the shaft out of a GM column, mid 70's, as it is a double D type shaft. Just cut it down and weld it in. The binding went away after I installed it and a tilt wheel and added that second ujoint.
Now, suspension! I had a 3.5" lift on mine when I put in the PS. The new gear box sits lower under the frame then the old one, so you may have to do something to the track bar or tie rod. You should get lots of help here soon though, good luck.
