In November issue of Camaro Performers, They had a tech article on a Spicing up a v6 Camaro with exhaust and pretty much all new suspension components. The rear end was completely covered in rust. They used this:
http://www.eastwoodco.com/shopping/p...ProductID=1130
It came out looking really good after painting it.
They note that the aerosol version of this product might be a better idea than the brush on. This might be opposite is you have more rust.