Who the hell needs two underhood air compressors?   Why go through all the hassle of trying to setup such a bulky and unessential menagerie of engine driven accessories?  Hey, I've got a lot of free time on my hands.  The installation is not that difficult when looking back with 20/20 hindsight.  But I admit it was not much fun going into the project blindly.  

         Background information:  My Jeep is a '78 CJ-7 with an AMC 360.  This motor replaced the stock 258 1 bbl and it came out of an Ambassador.  Both motors had York compressors from the factory so I had all the brackets I could need...except to mount two Yorks side by side.  BTW, my CJ came with factory A/C.

         The AMC 360 came with the York mounted horizontally due to limited hood clearance, and it stayed that way on my Jeep running air tools for 2 years without blowing oil or any other problems.  I removed the A/C when I swapped motors and kept it out until this summer.  The second York will not fit unless the compressors are mounted vertically.  I attached the compressors together using 3/16" thick, 2" wide, and 1 1/2" deep C-channel.  It was a snap to drill the holes using the unmounted compressor as a template.  Grade 8 bolts were fastened through the C-channel to all 8 holes in adjacent sides of the Yorks and the inboard York was mounted in the factory bracket.  To make enough room for the twin towers I relocated the solenoid towards the back of the right fender.  Besides needing a pair of new belts and some creative rerouting, the only other necessary part was a different pulley for the PS pump.  I got the proper pulley from a mid-80's Monte Carlo; it sits much closer to the face of the pump than the stock double pulley.  When attempting to remove the old pulley from the pump I used a 3/8" allen wrench and a breaker bar to unscrew the pulley from the shaft.  After 45 minutes and bending the pulley I knew that this could not be the right way.  A call to Marlton Auto Parts, which happens to be owned by a friend, set me straight.  I brought the pump into the store and they showed me how to remove the pulley and install the Monte Carlo one using the proper tools.  It took under 5 minutes to swap pulleys using the correct puller/driver tool.  Fortunately, I did no damage to the pump shaft in my uneducated attempt at removing the the old pulley.  The pump was then reattached to the bracket and measurements for the new belts were taken.  The inner belt (15630)runs from: Crank-Alt-PS-Crank.  It passes between the fan pulley grooves but doesn't contact the pulley.  The outer belt (15575) runs from Crank-York 1-York 2-Fan pulley-Crank.  This belt is not adjustable and was installed by removing the clutch from the outer York and pulling it back onto the shaft.  

The inner York runs the A/C and uses the factory hoses.  The outer York runs the air tools and uses a long list of parts.  These include:  

Wiring the compresors was quite simple, as the factory compressor for the A/C runs inside the wiring harness and the outer compressor runs off of a switch mounted in the dash and plugged into an accessory tab on the fuse box.  The switch runs through the firewall and to the pressure switch.  Connections on this type of pressure switch are from the switch to L1 and from the York clutch to T1.  The info included with the switch is lacking, but from left to right the 4 poles are L1-T1-T2-L2.

The install would be much easier if I had all this info beforehand so I hope somebody else does the swap using my information.  But again, who really needs two compressors underhood?