yep, NY4500, 92 (mid year I think) and up as mentioned. 3/4 tons and up and some 92-93 1/2 tons I hear.
I believe the magnum and LA blocks use the same bellhousing, so that shouldn't be a problem. The NV4500's use a hydraulic clutch whiuch may take a little work, but having a donor truck should net you the parts. T-case adapter should be available from Advance I'd guess, if needed. Floor hump may need some work for clearance or shifter location.
Someone on here has done it in a RC, can't remember who right now. loook around because I remember seeing it mentioned recently.
I also hear the old Clark 5-speeds are very strong, but very very hard to find.
Another idea/question. Does the NV5600 6-speed's bell housing fit a 360?