Leathermang: If you are building a system from the ground up, I would highly recolmmend talking to the people at www.ackits.com. They will have all the parts you need, and are capable of fabricating the parts you need made special for your truck. Furthermore, since I have [unfortunately] had to educate myself on automotive a/c, I know that a very highly respected compressor out there is named a "Diesel Kiki." Another very popular compressor is made by Sanded, although the Diesel Kiki is better from what I have heard.

Make sure you pick up one of the universal parallel-flow condensors from ackits.com, they are cheaper than anything you can buy at a parts store or junkyard, they come in various sizes, and they are designed for r-134a, which I assume you plan on using.

Good luck,

Greg
'84 300D

P.S. I'm not affiliated with ackits.com, but I have had unbelievable customer service from them, as well as very reasonable prices, so I recommend them any time I can! They deserve the "props."