Swapping a/c system from '94 to '90?

Not sure if this belongs in OEM or modified discussion....
I have a bare bones '90 4.0/spd Sport. While looking for some parts, I ran across a complete '94 which has working a/c. Now, I would *really* like a/c
How feasible is it to retrofit the a/c from the '94 into the '90. I'd have both vehicles, so I could grab anything necessary, although it looks to me that the wiring changed a bunch between '90 and '91....
I imagine I could get most things to swap over, but the hvac controls (wiring, cables, and vacuum lines) look to be a pita, and I'm not sure how the system bumps up the idle speed when the compressor kicks in (is the computer changed, or some additional input provided?)?
Is this worth doing if I don't mind have the Jeep sitting around for a while?

I think the compressor mounts diffrently and I'm not sure if the mount will swap between years.

If you're selling the ac bypass pulley off the 90 send me a PM.

If I do swap the a/c, you can have the pulley. I don't know what the time frame would be though...