Posted for "Matt & Bobbi  Hapgood" <hapgoodm94@alum.darden.edu>:

I've done this modification to my plane.  Shaved the entire bottom intake
off the stock 320 cowl.  I also have 4 separate pipes with no crossover on
the exhaust.

At the same time I removed the bottom intake I also removed some bulges on
the side of the cowl that I had previously added (for an earlier exhaust
system).  The speed improvement was noticeable, but with both of the changes
I picked up about 4 KTAS.

This isn't as large as the change recorded by Chuck, but since my work was a
test mule, the finish work wasn't very good.  Maybe if my lower section were
smoother I would see more improvement.  Another positive is the plane looks
better.  On the down side, I have had more than a few problems with cracks
on the exhaust system - which I purchased from the same guy that makes the
exhaust for Chuck.  I have cracked the #1 and #3 pipes at the cylinder
flange TWO times EACH.  This is a real problem.  I have about 150 hours on
the exhaust.

Chuck makes a cowl for the angle valve 360 which eliminates the bottom
scoop - and I purchased one from him last year.  It is a nicely done cowl,
and mine will be installed soon.  I've been using my old cowl for a test
mule so that I don't have to hack up Chuck's nice work.  I hope to get a
little more speed from the smooth cowl versus my wart and wrinkled infested
snout...

Matt