Perry,
Did someone say you are using a stock, cannister type exhaust manifold? If
so, which type is it? I've seen three different ones: a low volume, no
baffle type with angled flange  to exhaust pipe; a larger, about 6" diameter
cannister with exhaust pipe flange at 90 degrees to engine pad and a similar
one with internal baffles.
Andy Venable used the last one with an 18" exhaust pipe and believed his was
no louder than a Lycoming. I'm planning to experiment with this type in
spite of the weight.
Thanks
Peter

Peter:

I'm using the stock exhaust manifold that came with the '86 NA engine.
It's a heavy cast iron thing. Exhausts to the rear pointing down about 45
degrees.  I have a short 6" pipe with a 45 degree bend to get the exhaust
pointing rearward again.  Pipe was made at a muffler shop four years ago
and has shown no sign of wear, over 400 hours now.  The cast iron takes
all the abuse.

I don't know that my engine is that much louder than a Lyc, but the
sound must be in a frequency range that travels much farther.
Perry

 
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