I had an ex MOD 90 which had been fitted with a Discovery 3.5 V8 and it's short stick box, when the box gave up I fitted a LT95 4 speed box from a Range Rover. It used the same mounts and prop shafts the only mod was I had to cut a hole in the seatbox (at the front) for the transfer lever but the main gearstick came out of the original (LT77) hole. I got an overdrive and the thing went like stink with (reasonable) economy

@wireman
I've agreed on a 3.5V8 efi from a '92 Disco and a ZF4HP22 autobox out of an '89 RRC , so apart from the engine-chassis mounts all should fit ok, bar some mods to tunnel/seatbox/floor. Booked to do the conversion w/b 16 April so all fingers crossed.
Cheers.

It's been quite a haul and the engine-autobox conversion turned into a refurbishment as we found a lot more rot than I thought, had to find / fabricate various missing parts, bits and pieces, do a dash rewire and extra work for the MoT.
All done now, MoT with no advisories and the auto 3.5 V8 Efi is lovely Looks like I got a good one, thanks @Terry O Sullivan, pulls really well, smooth and sweet and nippy for a 3.5. Higher compression Disco V8 rather than the lower comp. 90/110 V8 I've had in the past. The auto box is very good too, smooth and quiet with good kick down, locks up at just below 50. The combination of V8 and auto makes driving a joy, especially as my arthritic left foot can now rest easy. Pretty much as LR intended although the ECU is in an unusual place (but it's dry and warm) and the shifter is not in the centre but I think it's easier to use here and wanted to keep my steel cubby box.
So at last, I have a V8 Landy again

A full account of the trials and tribulations doing this conversion can be found on my other forum home: https://www.lrukforums.com/threads/3-5-v8-efi-from-a-k-reg-disco.232297/