It depends on how you want it to look. When I did my Jeep I coated the underside of it with POR-15 and then sprayed on undercoating to deaden the road noise, and it knocked it down some. Some undercoatings can be oversprayed with paint. I'm not sure if our trucks were painted body color or black under there.


Paint & Body Shop moderator
A lone amateur built the Ark. A large group of professionals built the Titanic.