I just did this swap on my 86 720 2WD, LHD, it was fairly easy, but like it's been said, you need the entire steering system to include the column, connecting shafts, rag joint, box, lines, pump and all the brackets and bolts to make it work. This will more than likely give you a tilt steering column too, which is a plus, so you'll also need the plastic covers for that too. If you are really lucky, you can get the wiper delay relay and add that option too! It will simply plug into the existing harness under the dash....and if you really like delay relays, you can find the dome light delay and connect that to your existing harness, these are all plug and play as I have found so far.
Most of the models with PS are the ST model, so you can also find other options that will bolt on to your truck if you find an ST model, including Power Windows if you are extremely lucky, but that requires you to change the doors too, and some wiring.