The full article is in Sport Aviation, Dec 2001, pg107 or

http://www.aircraftexhaust.net/

The web site makes no mention about the new PVC tube mockup service mentioned in the article. I do think from reading their site though that they would be an excellent candidate for jig welded tubular manifolds...intake and exaust.
What about all of the automotive performance aftermarket companies? There must be several companies making aluminum manifolds.
...Chrissi

Thanks Chrissi. Sounds expensive.
Most racing manifolds are tuned for 8,000 to 10,000 RPM.
We have a bunch of 2.17 to one psru's out there so our RPM
limit is about 6300 for a reasonable prop speed. When Tracy builds
a 2.85 to one psru we can up the RPM to 7500 or so, get 20 additional HP or 
more and maybe use a racing manifold. Also a lot of racing manifolds are too 
high profile for our use. None fit the stock turbo to my knowledge as
most use the stock manifold when turbo charging. It is way too
high profile for our use. Here is a low profile custom manifold done
years ago by Racing Beat from tubing. One fine job but expensive.
 
Paul Lamar
 
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