I fabbed one up last year for my cougar
4 sided.
I also have a cool air feed that comes into the bottom of the box

The only thing I haven't done yet, is get the rubber gasket
that mates up with the hood.

I made mine first out of cardboard..
then I used Corrugated Plastic my theory was
that it would work much like a thermopane window.

I'll see if I can get some pictures.. I still have the one
piece cardboard template around.

Although the mention of Fiberglass now has me intrigued
I may wrap my existing shield.... hrmmm....

Anyone have a source for inexpensive gasket material
(sorta like a trunk gasket)

99 Cougar V6 Tourmaline Green: MTX, KKM, Borla Dual...