After reading about how Terry used Zilla Mat as the foundation for the super successful sound deadening solution in his truck, I decided to give it a whirl. Here's Terry's great thread: Starting my 72 camper special project update 4.10.
Since I plan on using a different cab some day, I'm not trying to implement a solution as comprehensive as Terry's. My plan's to lay this Zilla Mat down on the cab floor, then install the OEM-style rubber mat over that. I'm hoping that this improvement will make #50 more fun to drive over ~40 MPH, since with the completely bare-metal cab it has now, it roars like an African lion imitating a dial tone.
I ordered the 50 square foot roll from ZillaMat.com, and they charged $86.99 on my card. The goods arrived just a few days later, in a heavy box! Here's how it looked.
Those papers in the box were an ad, and instructions. I'm not sure whether that ad's describing the same stuff (possibly with a different marketing name). Here it is, with the front on the left and the back on the right (click on the images for a much larger and clearer view):


And here are the instructions:

I found this roller in the box. I was impressed that it was USA-made, since so many places buy this kind of product from China.
Here's the roll. It's the biggest and heaviest piece of liquorice I've met in my entire life!!!
I'll keep you guys updated with how this goes, although I can't promise to do as nice of a job as Terry did on his!!!
Robroy