Tomorrow I am picking up the motor to start my Diesel swap! It's a 1990 Isuzu 3.9L 4BD1T with a GM Bellhousing adapter. I'm super excited to say the least. Since it has the adapter to run a GM trans, and I'm a MT guy all the way, I plan to run a stout 5 or 6 speed behind it, either the NV4500 or NV5600 most likely. It seems everyone runs a different transfer case for different reasons and I'm trying to decide which to run in mine. This is going in an 88 GW, with factory D44's front and rear currently, though I intend to change those for built 1 ton axles in this process. I will be running locked diffs with 37s so I'd rather buy once/cry once and not have to worry about breaking on the trail. I want to settle on a transfer case before axles so I can decide whether to run a driver or passenger side diff front D60. I want to be able to drive this Jeep to Moab someday, wheel without reservation, and drive home. Of course I'd love to eventually have an Atlas under there, but I would rather spend that money on other things as this is not going to be a cheap build.
Side note: I do have a Dana 20 already which needs to be rebuilt, and I am not afraid to rebuild/upgrade anything. Ideal budget would be ~$1500 including all adapters.
So in order of importance, here's what I need in a TC:
Durability/Strength - must hold up to diesel torque! I'm not excessively hard on things but I can't be blowing apart TCs left and right
Lower than 2:1 ratio - even if that means going with a low range upgrade kit
Adaptability (would love some options that will bolt right to a NV4500)
Cost
Clocking that doesn't leave the case vulnerable
Twin stick-able
Not a factor for this build:
Full time 4wd/AWD
Weight/size