Don't use the fiberglass insulation. It would work but isn't the best for that. Plus if it gets wet then it needs to be dried out. I use the bubble-wrap style hot water heater insulation (the foil-sided bubble wrap). I put a 2'x50' roll in my truck, it's at least double layered everywhere. It's quiet and stays cool as well. We've always used clear silicone to glue it down, and it works well. My doors close nice and solid and when you knock on them you get a solid "thud".


1946 GMC Pickup - S-10 Frame, 455 Buick, TH400, original patina.

My 46 GMC on Photobucket