I improved the interior noise levels in my 70 Challenger R/T with the following:
- Glued used OEM floor insulation (jute plus a tar-ish backing ) from a junkyard minivan (lots of flat material, and dirt cheap) to the insides of the door panel plastic. needed to avoid the space where it screws to the bracket, but otherwise pretty easy.
- Used Dynamat to cover the rear seat floor, package tray metal, and all of the openings around the trunk divider, since a lot of noise comes in there. I also added the minivan floor insulation to the backside of both seat cushions.
- Ditto above for the rear quarter trim panels, covered the window mechanism access areas.
- Stuffed insulation into the sail panel area from inside the trunk.
Basically, I wanted to stop noise transmission from the trunk area into the passenger compartment. All of the modifications are hidden.
I HAD a noisy rear axle (still do, another sad story) but now I really have to listen to hear it.
Mark