Mr P Body said to use exterior grade plywood so that's what i used.

""So, the polycarbonite and/or the lexan stuff would probably control heat better than aluminum wouldn't it?""

68,
I received an email from the manufactures of the Tuffak product. They said that their material is a better insulator than aluminum but it is not as good as phenolic. But I have not seen a phenolic sheild for sale by any manufacturer as of yet.

This is a picture of the one that I made and I have been using it for the past couple of weeks. So far it has not changed color and it has worked good enough to keep the smell of hot fuel out of my garage during cool down.

The clear material blends in decent with the other colors under the hood.

I even added some vent holes in my air cleaner base to allow the heat to escape upward into my air filter and out thru the holes in the Rallye hood.
EDIT: Dumb idea, don't do this.

That pretty much makes the air filter useless.

""Looks to me like you just introduced hot, unfiltered air to the carb with the addition of those vent holes.""

HMMMM, good point. I will have to plug those back up, thanks to both responses.

""The clear plastic thing is pretty, but pretty useless.""
Absolutely not!! The carb bowls are now cool to touch after a drive and before they were pretty darn warm before the motor was shut down. Before I tried this pretty thing, the fuel was getting so hot during cool down that it was boiling out and the smell from it caused my garage to smell and now I do not have this problem. The pretty thing is deflecting the heat from the engine to go around the carb to help keep it cooler during idle conditions and shut down. After a 30 minute cruise and romp drive I stopped in an open parking lot and left it in D with the emergency brake applied and I got out just to check the temp of the bowls and I was surprised that both bowls were cool to the touch. I got back to the garage after another 20 minutes or so and shut down the car to find the bowls were still cool. Then I checked the bowls again after about 15 minutes of cool down and they finally started to warm up. After about a half hour of the hood closed during cool down I checked the bowls again and they were a tad warmer than before but not even close to the temp that I used to have before adding the sheild and I still did not have the garage filling smell as before.

If you think that this pretty thing is useless, you might want to contact Holley and Mr. Gasket and tell them that their carb heat sheild is useless too and while your at it tell the other members of this board that the idea of a carb heat sheild is useless. All I did was find another material that is actually better than the aluminum units for contolling heat transfer and that most of us can use to fabricate with while using simple tools from our own tool boxes.