It would help to know what Jeep you want to convert? It looks like you have a YJ in your icon photo? If so, I thought all YJ's had P/S? Regardless, just as steedy.foot mentioned, you need the correct intermedate shaft, the P/S gearbox, pitman arm, supply and return hoses, pump w/ pulley or serpentine wheel, mounting brackets for pump and gearbox (not 100% certain on the YJ as I've never seen one w/o) and depending on the year of the vehicle, either a longer serpentine belt or some upgrading to your existing pullies as mentioned earlier.