insulating a 359 Pete

Good call on the chickens. But just as a back up dynamat works great just lick and stick. And you don't even need to worry about the dynamat running away from you when your not looking.

 

Dynamat dampens panels from resonating. That's why you just stick a sheet on a flat panel and it doesn't need to cover the whole panel. I would use dynamat on each panel and then some good closed cell foam for temperature (also good for sound) insulating.

Something I need to do badly in mine.

 

That's very true, couple that with some Lizzard Skin or equivalent on the firewall facing the engine and floors facing the ground and you'd be at the top of the class.

Take a step further and get some of that chrome vehicle wrap and install it on the top of the sleeper and cab to keep the radiant heat from the sun down. Then tint the windows with the new heat reflecting tint that the Mercedes use and you would be doing the best you can do against summer heat in our trucks. Plus the air conditioning would work that much better.

 

IIRC, Dynamat does not have as good a heat tolerance as the other similar products. Remember reading negative comments from guys who put this stuff on floorboard above mufflers, & it turned the rubber into taffy, sliding from it's original placement
When replacing the carpet on a W-9 years ago, I coated the floor with that white elastomer paint people often put on mobile home roofs (Kool Seal). I later coated the under side of the floor, (messy job). Helped, but I think the previously mentioned coatings would be a greater benefit.