The following is a copy of a discussion that ocurred on the Yahoo site.  I have posted it here as a reference thread for others that may want to consider the subject.  Hopefully, I have properly credited all original authors.

Hey FMC Group, I am replacing the cracked drivers side exhaust
manifold on my coach. (also going with duals) We still have the org.
440 I with stock manifolds. I was wondering if any of you have tried
having the manifold and or the exhaust header pipes coated with any of
the new ceramic coatings? Thanks, Jerry #699

I have not myself, but a friend of mine who restores muscle cars (many
with 440's) swears by the process. He says it does wonders for
keeping the engine and engine compartment cooler.
Gregory Miller

Thanks, I took my new manifold to my friends strretrod/ machine shop to
have it milled and he said the same thing. I just want to see what the
group had to say. jerry

Jerry -
Be sure to use the center drop exhaust manifold as the headers will cost you
fuel mileage with the HEAVY motor coach LOAD.
HAPPY TRAILS - Leslie Hoagland - FMC #0938

I assume this is an internal coating and how much does it cost?
Stephen Heinrichs

Hi, no this is an external coating. It has been used for sometime now
by NASCAR and high performance shop on headers, manifolds, turbos and
the like. I have not received my new dual exhaust from Les, When i do
i will take them by and get an est. but i was told $100 to $125 on
the new exhaust manifold. I don't think you would want to do the
mufflers but am considering the manifold and the pipes to the mufflers.
jerry # 699

I replaced my exhaust gaskets with the copper ones. They work great! I bought
them through J.C.Whitney. Of course, the copper gaskets don't have the shield
that goes up between the manifold and valve cover. So I used the 2" wide
woven exhaust wrap and secured it with thin stainless wire. I did this about 8
years ago, and it still looks new.
#632 (for sale)
Kevin McMullin
Bear Delaware