For the seal and bearing, your best bet is to get it apart, and get the actual seal/bearing number. IF it isnt stamped on it, or no longer a valid part number, a search by size will turn up the correct modern part numbers.
The seals and bearings are likely available at a NAPA or similar store for lots less $$ than you will buy one that has a ford part #.
As to the power steering, that would be more ford specific. And there were a lot of variants to the 4000 series. And several different styles of power steering. So knowing exactly what model/set-up you have here is important.