Have thought about doing this for a while. 6 speeds were/are also used in bigger canter FE so it should all bolt in, except for the transfer. May have to run divorce unit, something like a NP205.
Gearbox Model number has a S5 at the end, 6speeds are S6 for the equivalent box.
Tcase does represent a slight issue (well for me anyway), high ratio is 1.09, but basically any other tcase you can get will be 1:1. I guess 9% taller high ratio will be fine for most canters, but mine with the big XZLs is already almost too tall, doing 2150@100, another 9% on top would be too much.
Best solution I found to that would be to go from 5.29 diffs to the fg649 5.71s which would be 8% I think, so bringing it back to where it is now.