Quiet down my cab

[cppursell]

Hi,

I want to quiet down the cab in my '67 Chevy C10. Right now it's bare metal all around (except for this tar-like insulation on the floor). I'm planning on putting in a new rubber floormat on the floor, but I thought putting some reflective insulation from Home Depot under the floormat would quiet things down even more. I also thought of putting some more insulation behind the door panels...

Are there any other tips you guys have to quieting down my cab, so I can think while driving on the freeway? Thanks!