1992 e250 exhaust ????

Hey all Im in a bind here and need some help. I am working on a buddies 92 e250 4.9l automatic and need to replace the front exhaust manifold. My questions are

1 what all has to come off the engine to get to the manifolds 2 do I have to remove the rear manifold to get to the front manifold? 3 are there any hints or secrets to getting the manifolds off Thanks for any and all replies Steve