Truck Sound Deadener Matting

Truck sound deadener is the single cheapest thing you can do to make an old cab liveable at highway speed. A bare steel floor and firewall act like a drum skin; a layer of self-adhesive butyl matting stops the panel resonating and takes a surprising amount of heat out of the floor at the same time.

You do not need full coverage. Roughly 25 to 50 percent of each large flat panel, laid in the middle where the drumming is worst, gets most of the benefit. Roll it down hard so it bonds, and get it in before the carpet and headliner go back.