Thanks for the info, Ed....One point of interest is that I have the stock
cast iron manifold inbetween the engine and my tailpipe. It would seem that
the cast iron manifold is absorbing a lot of impulses, because everyone who
has heard my engine run states that it is not that loud.  Perry Mick
mentioned that he has a standard exhaust pipe following his cast iron
manifold as well, and has had no problems with it in the few hundred hours
he has flown with that setup.  (He told me that when I was inquiring about
the need for stainless exhaust pipe after the cast iron manifold).  Don't
know how much energy the cast iron absorbs, but it definately absorbs the
heat so the pipe doesen't get as hot.  Curious minds want to know.  Take
care.  Paul Conner