Right at the jamb area your showing where the 1/4 swoops in to meet the carpet sills...underneath the 1/4 panel is a rubber-foam ball that was put there by GM as some sort of weatherproofing.. but it retains water and rots that area from the inside outward.. you need to get ii there and remove that.. mostly but blowing a hole right in the rust and picking it all out and vacuuming and flushing with water.. load it back up with 3M Rustfighter then weld it all back up.. mud it up and smooth it and paint it.. it'll be a weak spot for the car so make sure you fill that cavity with as much rust proofing as you can
tom @ camaropacecars.com ( remove the space between m,@,c)
Posts: 13412 | Location: Arlington Mass | Registered: 01 May 2005
Body guy will be welding in a piece.Just took her in fri so nothing has happened yet.Will drive by later this week and see what is up with it.Got a couple more spots to fix but they are normal spots.
They did the same thing in 1970. Foam strips were placed in the quarter panel lips-they did an excellent job of holding moisture and rotting the quarters out.