Not sure if this is the right area, but when I replaced the heater core and I took out the heater box, I lost some of the insulation/carpet/sound deadening material that was up there.

It ripped, it dusty, and in pieces.

It's probably not a big deal, but what are my options to replace it? It probably does almost nothing, nut without removing everything, dynamat doesn't really seem like an option. Do they sell the material?

 

In my 67 the rubber backed insulation for the firewall IS the seal for the heater/ac box inside the car. These are available for all A bodys im sure. If you only want to patch it im not sure what to tell you. If its all gone from around the heater box you could probably get some sticky back foam seal tape from Lowes or Home Depot

 

I'd bet it's all deteriorated like it was in my 66. The repop's are fairly inexpensive. You will need to remove anything screwed or bolted to the firewall to replace it.......

 

After what I just went through for the heater core, I'll sell the car, or total it before I take it apart that far again.

Thanks for the warning!