I tried to sound and heat insulate my black '69 Super Bee.

I had the entire interior (floor, doors, firewall, ceiling) coated with Lizard Skin spray on heat insulation.

I put a layer of butyl rubber sound insulation from RaamAudio (similar to Dynamat) on the firewall, floors, ceiling, quarters, etc)

I then put a layer of closed cell foam that is supposed to be a sound barrier over everything.

I used carpet with the extra thick rubber backing.

The doors close with a nice satisfying thud, none of the panels sound like an empty drum if you knock on them, and It is certainly quieter than it was previously.

That said, the car has a 3" exhaust + 3.91 gears and you have to pretty much yell to have a conversation in the car on the highway @ 55-60MPH.