Hey I think I found it:
nostalgicairparts right?
that's the place. Unfortunately, they don't sell the CUCV kit anymore, as they were having too many problems getting the add-on evaporator.
BUT.... as they say, there is a way around it. NAP sent me their 265 series evaporator which is a replacement unit that has defrost, a/c and heat in one unit. This requires removing the old heater core, rather than just finding the room and installing the evaporator. NAP sells the evaporator as a generic kit, just specify you want the CUCV installation kit.
I removed the heater core (with left me with holes in the firewall to run the hoses), installed the evaporator in its place, and then mounted the a/c compressor in the area between the passenger alternator and the front battery.
The mounting kit comes with two large brackets that fit behind and under the passenger alternator and a pulley that fits into the center of the crankshaft pulley. Remove the alternator, install the brackets, put the alt back. Remove the crankshaft pulley, put the new pulley inside the crankshaft pulley, reinstall with the supplied longer bolts.
Inside the truck, remove the heater core, install the evaporator, remove the glovebox (not enough room to fit the evaporator if you don't do this), run the electrical wires and ducting, run a/c and heater hoses and you're about done.
Attached are pics of the mounting kit, the pulley and compressor after install
The mounting kit comes from a place called Component Parts out of Fort Worth TX. Kit is labeled "5255 86-87 Chevy Blazer 6.2L 2 Alt".
Cost of the kit was $995, extra odds and ends parts cost me about $40, tools I didn't have was another $150, then the cost of getting it vacuumed out and freon added.