Confession: I'm a mechanical engineer and I work for a company that specializes in robotic integration and custom machines. We have a full CNC machine shop and some super talented people. I designed the cooler in ProEngineer and put the drawing in the shop. One of our machining wizards took a block of aluminum that I bought and whipped that baby out in a couple of hours on a MAZAK vertical machining center.
As far as cooling is concerned, I have no data but with the truck stone cold I can make a 5 mile trip to town and back and the cooler is very warm to the touch. Plus, it adds about a half a quart to the oil capacity of the transmission.