Hi Rusty;
You probably already have all the responses on this that you need, but I'd
like to second the endorsement of the pour-in-place foam. I've used the two
part polyurethane mix from "Fibre-Tek". I find it particularly useful for
building ducting under the cowl. use aluminium foil to wrap around items
that you need to keep it out of (such as the cooling fins on heat
exchangers), then use cardboard and duct tape to create dams to contain the
liquid foam, and in minutes you will have hard foam that is easily cut with
a knife and sanded into the desired duct shape. Very easy and efficient.
Cowl shapes are also very easy as well. It actually can make fibreglassing
a blast..... Doh! Did I just say that?!!! I must have inhaled too much of
it...

S. Todd Bartrim
Turbo 13B RV-9Endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm

   "Whatever you vividly imagine, Ardently desire, Sincerely believe in,
Enthusiastically act upon, Must inevitably come to pass".