Several years ago I got a new header panel from GBodyPaarts. Much better quality and thicker than OEM. Coated on both sides, unlike the factory panel that is in there. At the time they offered it with or without the J channel welded in. I didn't know any better so I chose without and welded it in myself. The width of the insulation determines where to weld it in. I used their rubber kit too, but I think it was not as good as it should have been.