Factory Trunk Deadner

Raptor Liner is really nice (I've used it) but it can get spendy and once mixed, you're stuck with using it right away. Similar to what others have suggested already, I've also used this undercoat from RestoRick. It says it's rubberized but actually dries quite hard and rigid like the original. Works really well too inside quarters and other areas: Restorations by Rick Kreuziger - Product and Component Restoration Detailed Information