If you plan on lifting your truck much, you might want to consider upgrading to the newer 5-speeds (84-up). They are about 6" longer and allow for a longer front driveline. I have installed alot of these and they are a very simple install if you have a shortbed, if not, you will need to have some drivelines either modified or custom ones made. If you have a shortbed, you can just use the drivelines from the donor shortbed truck or any 4Runner. You then rotate your crossmember 180 on a verticle plane and redrill one hole on each side where the old front hole lines up in the center of the frame. Drill a 1/2" hole through the frame and install a 6" 1/2-13 bolt. You will end up with only 3 bolts per side if you use this method, but I have not had any issues with this.
If you have any questions, feel free to ask.
Jeff