Posted for "Rod Pharis" <rpharis@teamimc.com>:

Fred,
 
 Your comments are technically correct.  However, you appear to have not
 considered applying the ceramic coating to the tubing ID as well as the OD.
 The manifold CRES wall material should be cooler, and also radiate less.
 That's win-win!
 
 Rod Pharis


...snip...
 
  If you wrap or coat the exhaust manifold, the wall temperature is going to
 be raised, and the strength reduced.  From the figures, we an see that
 100-200F can make huge differences in strength.  The worst thing to do is
 wrap the manifold with high temperature insulation of the type frequently
 sold for automotive use.  I once saw a plane with braided stainless steel
 mesh over the manifold which is fairly bad.  The ceramic coating probably
 has the least effect in increasing manifold wall temperatures, but there is
 still certain to be a negative effect.
 
...snip...