Pics may help to get a good answer. If by rust you mean surface rust then I would spend some time with a wire brush and get the loose stuff and dirt off. POR is great stuff if you follow the directions and do the prep work. It hates moisture and 1 drop of sweat in the can will ruin the whole can. If by rust you mean scale rust that comes off in chunks then you need to go a different route. Wow and 11000 mi original? Love to see some pics and hear the story.

 

Thanks Sampson. It's basically just Surface rust. So I had planned on getting under there with a wire brush and just getting all the loose stuff off. I inherited the car from my Granpa who bought it off a lady a couple years before he passed. I guess she was the original owner and never drove it. The car is in amazing shape, just underneath it's a little rusty. I just got a new exhaust put on last week and will be driving it backt Chicago this weekend. I will post more pics then.

 

This is what POR15 is designed to do... Paint Over Rust.

 

I don't know about por 15 on bare metal but will tell you that nothing stcicks to bare metal like epoxy primer. I sandblasted my frame and used a 1k epoxy primer from martin senour. Then used rustoleum satin black that i thinned with acetone. I didnt use these products because they were cheap but because they are tough and proven and have a great finished apperance. Wouldn't want to take it back apart for a couple hundred bucks in materials. Now I wouldn't use the spray-bombs I just don't think they get the build compared to a spray gun and a couple quarts of rustoleum and a gun are probably the same cost as the areosol cans. Also had to do a slight frame pull on the right rail after the frame was back in the car and was shocked how well the paint held up to the chains and hammer blows that followed. And the stuff spotted in so easy!