...5.3LS and a 6L80 Transmission... is the route I am going to follow

My Question: Is there a way to use the original GM transfer case ?

What is the alternative?
1. I found a commercial offered adapter to bolt on a LT230 (from a Defender I think)
Advantage here would be that the LT230 fits from ist size very well
2. When a LT230 bolts on -- will the original Range Rover transfer case (a Borg Warner TC??) bolt on too?
3. I would like to go with the GM Transfer case that belongs to the LSx / 6L80e drivetrain…
as I need to customize the driveshafts anyway I would appretiate your thoughts on GM transfer cases coming with 6L80e...

 

The issue is that GM cases are generally driver's side drop for the front driveshaft. Disco axles are passengers side differential so the driveshaft angles come out pretty bad, and avoiding the trans pan could be tricky.

 

FJ80 axles. front and rear are both pass side drop and significantly stronger than the rover axles. Plus you won't have some monster diff housing that would need to be shaved down to avoid hurting clearance. There is an adapter out there that will allow most GM trans to mate to a LT230, friend just put one in his classic and it's a nice piece of machining and it keeps the stock trans/t-case mounting points...though I've heard that moving that all back an inch or so would be greatly beneficial for space in the engine bay.