The last two passenger side FMJ exhaust manifolds, I had to remove (in car) was not fun.
One I had to cut the exhaust pipe a short distance from the flange.
The other, I bought a dremel and used the thicker fiber-reinforced metal cut-off blades and cut the manifold-to-pipe bolts off. The manifold is so close to the frame rail, and there is just not enough space to do anything.
BudW