Posted for "Ed Anderson" <eanderson@carolina.rr.com>:

Ok, Todd.  Since no one else has jumped in on the 0.035 SS wall for headers,
I will.  I personally believe (in other words have no facts to back me up)
that I would go for a thicker walled tube - at least 0.049.  But, then you
have to consider my exhaust headers are made out of schedule 40 stainless
steel pipe rather than tubing.  Its thickness is around 0.10 wall thickness.

Yes, its overkill and heavy.  But, I had heard horror stories about what the
hot RX-7 exhaust could do.  A friend who owned and repaired RX-7s as
business for over 20 years related several instances of sever damage caused
by leaks in headers including one in which a small hole directed the exhaust
like a cutting torch and actually cut a frame member of the automobile.  So
just another point of view.  I think the 0.035 is fine for piston engine
use, but they do not have the heat and strong exhaust pulse to content with.

FWIW

Ed Anderson