I finally got around to changing out my cracked passenger's side manifold on my 1997 4.6 this weekend. I figured I would throw up a thread for future reference for anyone tackling broken studs/manifolds in the future. I mostly followed dart_440's thread on f150online, but most of it is common sense.
If you are planning to do this on the weekend, start soaking everything in PB Blaster throughout the week!
1. Goes without saying. Jack up the truck and remove the passenger's side tire.
2. Remove your inner fender. If you can't do this without pics/instructions there is no way you can tackle this project
3. Soak the exhaust manifold nuts and collector nuts again with PB Blaster. Let it soak while your are...
4. Removing the starter. There is one stud on the bottom of the starter with a 13mm nut that you can get to with a wrench. On top of the starter, there are 2 13mm bolts. You will need a 3/8 ratchet and 6" extension to get these out. I just let in hang down. It makes more room and is a must.
5. Loosen the 3 13mm motor mount bolts, but don't take them all the way out. I backed mine out about 1/4" to 1/2". To get to the 2 toward the front of the engine, you will need at least 2 6" extensions and a swivel adapter. I used a 1/2" ratchet. The 1 toward the back of the engine is easy to get with a 6" extension and swivel adapter.
6. Use your floor jack with a thick block of wood and put it under the oil pan and lift the engine. You only need to lift it about an inch or so to get a socket on the middle 2 lower exhaust studs. By lifting the engine it gives just enough room to get the deep socket in there.
7. Remove all the nuts, which if your lucky if they do break they will break flush with the manifold when they do. I also removed some of the top studs before taking the manifold off. I just tacked the nuts on and they came right out
8. Remove the exhaust collector nuts, you might need to cut them. Make sure you cut as close to the nut as possible so you have the most stud to work with. (I replaced mine with stainless bolts.)
9. Pry the exhaust back and pull the manifold off.
10. Now its time to remove all the old studs. Like I said, I used the old nuts and tacked them on to the stud to back them out. Both studs for the rear cylinder broke, so I welded 3/8" nuts to them to get them out.
11. Clean the head surface.
12. Grab your new manifold (mine was Dorman, $59.99 on Amazon with free shipping), gasket, and some anti-seeze and get ready to put the new exhaust manifold on. Instead of replacing the studs with new studs, I decided to go with flange bolts and lock washers. Well, I actually decided on stainless bolts and lock washers, but all the hardware stores near me were out. So I used class 12.9 M8-1.25 pitch by 35mm bolts for the manifold. Use a generous amount of anti-seeze on the bolts and start installing the manifold. Make sure you get the gasket lined up!
13. Tighten all the bolts up using common sense/feel. Just take your time and work from top to bottom, inside out.
14. Lower the jack a little then tighten your motor mount bolts then lower the jack all the way.
15. Tighten your collector nuts. Anti-seeze wouldn't hurt here as well.
16. Replace the starter. (anti-seeze here too)
17. Before you put the inner fender back in, start the truck and listen! This step probably isn't required.. but hey if it isn't sealed you will know!
18. Replace your inner fender.
19. Smile, you just saved a ton of money doing this yourself!
Hope this helps anyone in the future!