>Are there particular areas of the cowling that
should be stiffened?  Is the gel-coat cracking anywhere?  Do you see
flutter/vibration on the top of the cowl during flight?  Any deformation
after a number of hours?<

I added 1/4" foam to the top center of the cowl and some reflective metal
tape to the inside where the manifold was within about 1 inch.  That was
it. No flutter or any other problems.  The engine mounts will sag 1/4" at
the spinner so adjust the cowl accordingly.

James B. Frantz
Proprietary Software Systems, Inc.
www.angle-of-attack.com
LFrantz@compuserve.com
(952) 474-4154