The NV4500 is a few inches shorter so it looks like some modifications to the drivelines will be needed.
As far as gauges, some of the newer square bodied styled Trucks/Suburbans that had TBI engines used an electrical speedometer. You might be better off to find one of these. On my Suburban, I moved the fuel gauge down to the blank on the lower left and installed an aftermarket RPM gauge in its place. It looks stock.
1990 ¾ ton 4x4 Chevy Suburban
-Cummins Diesel - 12 valve - factory rebuilt
-6 speed bullet proof manual transmission - NV5600
-Gear Vendors Overdrive
-Upgraded Holset HX-35 turbo
-NP205 iron transfer case
-3.73 gears
1982 ½ ton Chevy Suburban
-6.2L diesel - high nickle crack free 1982 block
-Stans headers
-Ported heads
-Timing gear
-4 speed automatic
-3.08 gears
-30 mpg on freeway