Ok now it is time to attack that RUST
Can anyone give me some simple advice on what to do and is it right that even though I treat the rust on the outside it could well be coming through from the underside
Thanks

also
have hole in exhaust about 3" , can i fill that with Gun gum?
Doe anyone know if I can get a stainless steel exhaust for this bus 1988 magnum, the garage say not but thought I should check on here