How about the inside floor of the cab?
I am seriously considering it for my 48. On the 48 I am sure I will do the underside of fenders, cab, and running boards.
I have another project truck I think I will experiment with it on the cab floor and as far up the firewall as possible.
I have been trying to decide if it is a good idea to put down some of the thin sound deadener like dynomat on the floor, and then the bed liner over that. Right now I think it may be a bad idea because it could leave a place for water to hide, if the bed liner is bonded to the steel itself then no water. So do you sandwich the sound deadener between two layers of bed-liner, a thin one, dynomat, and a thick one?
I know the bed-liner will help quiet the cab a lot by itself, but I have Detroit diesel two strokes in both trucks, so they can use all the help they can get on sound deadening.
What do y'all think?
Grigg