You can go to ziggsters link, just look up ziggster on google.com
I did a system similar to his, just simpler but it works the same. Mount a gas grill tank in your bed and get an acetylene regulator, it will screw right into the tank. then run a hose to a shut off solenoid. it can be bought at RV dealer. Wire the solenoid so it comes on at half throttle when the switch is turned on. I used a push button switch mounted on the ip and then a lighted rocker switch on the dash.
From the shut off solenoid run the hose to the air filter container.
Look at ziggsters for the details but its fairly simple and I got by for a $120.
I have some pics of it in my gallery.