Rust proofing an older 911?
 

I live in the chicago area and was wondering is there anything that can be done to the non galvanized bodys to help keep them from rusting? Anything like a Ziebart treatment or something like that? Also what would a likely cost be for getting it done?

Did you want to do the work yourself?
You might be able to just POR-15 the sucker with a brush. I am not that familiar with the 911 body and undercarriage, but I did the process I've described on my 1969 VW Westfalia when I restored it and it worked great!

Jason

POR products works great. Just thin it a bit and spray into every crevice you can find. Undercoating guns with a long spray hose work well. YOu can modify the 90 deg spray tip to spray 360 deg while you fish it through rockers and such.