For my 55.1 3100, I used the system from Old Air products. I lived about 12 miles from their Fort Worth location, so in-person consultation was easy. I don't know the capacity, but it is adequate for Fort Worth, with caveats. It' a recirculating-only system, so fan noise is high. Just like an OEM system on recirculate. I don't have much insulation so it's slow to cool. I'd recommend you insulate everything in the cab to death. I'm tall, so the vents don't blow in my face. You'll feel cooler if your face is cool. I'd recommend you design a vent system that puts cold air on your face (and your passenger's face)
No engine problems with stock 235 and radiator without shroud.
If you think you may ever want power steering, go to Buffalo for the compressor brackets.
I use R-134A.
regards,
Leon
