After much research on the web, I decided that I really, really, needed an onboard air system for my Jeep.  So, I went to the junkyard to find a good, used, York air compressor from a slightly worn Wagoneer.  I was able to find one, remove it, and take it over to Grandpa Vande Water's for the installation process.  Now, Grandpa Vande Water is always game for some kind of project, especially one that involves cutting metal, welding, or making something that may, someday, be useful to someone.  My Uncle John also happened to be in town the day that we worked on it, so he got to help too.  Luckily, this project did not involve installing my distributor 180 degrees out of sync (like he did on my '78 Monte Carlo) so it went OK and we were glad for his help. (Sorry John! :^)   We basically created a mounting bracket that sits on the passenger side frame rail and uses a long belt driving both the alternator and the compressor.  The compressor has a pressure activated switch that switches on at 90 psi and shuts off at 120 psi.  I used an old stainless steel air/water fire extinguisher mounted to the frame under the passenger seat to store the air.  It holds about 2.5 gallons and is rated at 200 psi.  I was planning to mount a pressure gauge on the dash, but I just haven't gotten around to it yet.  All told, the project cost me in the neighborhood of $100, and I have used it many times to air up people's flat tires, rafts, bike tires, and blowing dirt off of things.  It was well worth the investment of time and money.  Plus, it was fun, and I'm a gadget freak.