So what is the best product for insulating the interior of our cars. I don't want to go with the stock tar BS. I was thinking using something like dynamat or boom mat. Ideas?

 

Dynamat is going to be one of the best. There are some other products much like it and may be just as good for less but i am not sure.

 

Rob did a nice job covering Dynamat on this thread.

https://classicoldsmobile.com/forums...rth-waste.html.

I used heating duct insulation from the local big box store. Used contact cement to put it on. I was happy with the results on my car.

 

Another lower budget alternative may be this:

It's like $17 /roll w/ 12.5 sq/ft coverage.

I've never used it. I've seen mixed reviews - Some say its great & some say it sags (its tar based as opposed to dynamat butyl) in high heat
.

 

I used Thermo-Mat sold by Sumitt. Was recommended to me and the performance is same as the way more expensive Dyna-mat product. Both the 3/16" one sided peel and stick and no-stick was used in insulating the interior on the frame-off of my 1970 F-85 W-31 post coupe. What a difference in noise and heat reduction from the floor/firewall. Make sure you buy the large diameter roller (also sold by Sumitt) for the stick and peel type to press in to corners and irregulars in floor pans. Pretty easy to install inside doors/quarters and firewall.

 

Thanks I will look up that thermo mat stuff.