[truckster]

I can't answer your question exactly, but I can tell you what I did on my 72 Blazer. The engine is an L31 Vortec and I'm using the serpentine setup from a 98 Silverado. I used the Silverado compressor and evaporator (it was pretty easy to modify my box to accept it). The condenser proved to be the problem, because it was too big and interfered with the grille support. I ended up using a 98 S10 condenser. The lines from the compressor to the condenser and from the condenser to the evaporator are from the S10, and the line from the evaporator to the compressor is from the Silverado.

Just to make it interesting, I kept the stock fan shroud, but I ended up using a fan from a 98 Astro van (smaller diameter) and trimming 1/2" from the fan blades to fit inside the shroud.

I also made an upgrade to the blower squirrel cage. I have been looking for the original link for the last 15 minutes, but I can't find it. Someone suggested using the squirrel cage from a 2006 Jeep Liberty. It's the same depth and diameter, but you'll have to cut the base off your old one and epoxy it to the new one. With that modification, it puts out a lot more air, since the Liberty part has more vanes.

With all of that, I have cold A/C in the summer and the heater keeps things warm in the winter, even with my soft top.