Here are some pics of what was underneath my roof. Decided to buy the aftermarket panel and weld it in.

http://img210.imageshack.us/img210/7002/dsc0300kw0.jpg
http://img169.imageshack.us/img169/3189/dsc0307tl9.jpg

http://img297.imageshack.us/img297/1208/dsc0311rq8.jpg
GOT RUST
http://img169.imageshack.us/img169/7600/dsc0316kz8.jpg
Giving it a bath in some etch
http://img210.imageshack.us/img210/5215/dsc0325jp2.jpg

So now what?? Por for this area or a thick coat of epoxy?

i would go with the por-15 to stop the rust.........

This brings back memories. I performed the same operation on my el camino. Your roof didn't look that bad though. Mine was rusted so bad you could put your whole arm through the holes in the sheet metal.

You can't see the damage that was under all the filler coat. I had large cancer areas that I didn't feel like keeping under a fresh coat of paint. I can also paint everything underneath there as well.

yeah use por-15, i coated my whole interior with it . good stuff and looks killer when its all dry and set.