Keep in mind- whatever you use for insulation can't hold moisture- it needs to be water repellent=. It it's not, it'll play hell on your truck metal, especially when exposed to salt on the outside and moisture on the inside. I'm aleady facing redoing cab corners again on the '78. BTW, mine is painted with dark metallic grey- it was an F150 color in the late 1980's. McMaster-Carr for all your needs.... Jim
