I just purchased some sound deadener/heat insulation for my 69, and I'm unsure about putting the foil side down against the floor, or the insulation/pad side down. My logic says to put the foil side to the floor to refect the exhaust/header heat, but I have seen many people put the foil side up with the carpet over it. Which is best?

I have some dynamat extreme that the foil goes up, but i also have some other stuff that is foil on both sides i have seen it go both ways, if one side is sticky that side normally goes down.

Good luck.

There isn't any adhesive on it. Just about 3/8" of what looks like industrial carpet padding or insulation, and a thin foil layer. It is supposed to keep out heat, but also act as a sound deadener.

Myself , I would always put the foil facing the hot surface and insulation up. That would be blocking the heat right where it starts. But you probably wouldn't notice a difference either way you use it.

It makes no difference from an insulation perspective. Reflective foil only makes a difference if heat energy is carried by light. Between floor pans and carpet it makes no difference. What you might want to consider is abrasion and friction.

Dale, interesting point. I'm not sure what you meant about abrasion and friction though.