[mrein3]

If you are starting with a truck that left the factory with AC, you can save about $1000 going stock over aftermarket.

There is nothing wrong with the stock system. The only difference between it and a modern system is that the modern system cycles on and off where stock is on until you turn it off. They will both use about the same amount of engine power while running.

I converted a non-AC truck to AC using stock components. You may find some useful information and part numbers in my post:
http://67-72chevytrucks.com/vboard/s...d.php?t=478564

According to my link above I got $350 into a stock system when starting from a non-AC truck and figured it would be about $200 to re-hab an AC truck (post 8 in link above).