I will (eventually) be running a 203/300 doubler in the Jeep, (after the NP435...GM version exists, but not very common)
adapter/LRG/adapter/t-case takes up
gobs of space,
and not nearly as pretty as Carwash's STaK,
but I should have enough levers to keep my mind occupied...
(if I saw the STaK before I had my doubler bits, would have a nice shiny STaK sitting between the frame rails right now...)
NV4500 is nice... overdrive... some say noisy... VERY specific oil requirement
they had a few different flavors... almost all of them need attention given to 5th gear under load... (just what I've read)....
Just for giggles...
Here's the difference in a Chevy C3500 NV4500 and a Chevy C3500
HD NV4500
C3500 (harmonic balancer on end)
C3500
HD (drum driveline brake on end, cast iron tailhousing instead of alum. above)