I didnt do it myself but had it done(by RedHead Gear in Seattle, $200) All that needed to be replaced were the seals, Toyota has a kit for $60.....funny thing.....same part number for a mini truck and a fj40

I suppose what needs to be replaced depends on the condition of the mini box.
I LOVE this swap, its by far the slickest way to do OEM PS. As you prolly know the 79+ block has the holes for the PS pump to mount, I used a fj60 PS pump. Used an aftermarket PS hose.....for a 60 or 40.....I forget, it was $30. Small trany cooler was added on the return line.
Damn does it drive SWEET. I replaced the rag joint, center arm, pitman thingy, and all TRE at the same time. Cruiserparts had a good deal on the whole package, I like the Fuji joints better than the 555 brand.....at least they havn't rusted yet!
As far as the shaft, you will need to make one cut and re-drill for the pin.....thats it!

will need a new boot and something else..........sorry brain fade.....
ALso the heat shield from the manual box bolts right up to the new PS box.
I kinda forget but I think I had to get the bolts for the PS box, I "think' they were longer......but I might be wrong......I know I used new bolts.
I cant thank Rick D enough for turning me onto this swap.....its SWEET. MOney WELL spent
I have another set up ready to go into my other 82 fj40. I can't imagine the casting will be around forever, 79 fj40 PS casting BTW.
If you take pics and write up how the gut swap goes I would love it, as I could be tempted to do the next one my-self.......or not :

but $200 isn;t that bad to have a box gone thru, turn around with Redhead was less than a day!!!!
John H