Whilst working on fixing my power steering leak and doing general maintenance (plugs, cap, rotor, etc), I've noticed that there is a LOT of debris from my starboard exhaust manifold...it is flaking away badly, leaving a bunch of crap in my bilge. The port side seems fine. Is this a common problem? How big of a task to change it out? Stock 7.4 MPI, 2000 model year.