on board air

I am planning to add on board air by converting an a/c compressor. I can't find the old magazine article on this.

1. will any type compressor work or do you recommend any particular type?
2. I think I remember that no special preparation of the compressor is needed and that I should drain the oil, replace it with Slick 50, spin the compressor to coat the surfaces, drain the slick 50, add an oil/water separater and go. Do you disagree with this or do you have any other recommmendations? Thanks, Don.

You can modify an old ac compressor to work:
http://www.jedi.com/obiwan/jeep/yorkair.html