A quick look at my Roger Bell book says an 81 car should have the engine and box as per the current Rover SD1, (5 speed LT77 gearbox) according to Rimmers this wasn't fitted with a self centralising bearing and the full kit is readily available.

https://rimmerbros.com/Item--i-GRID008899

but then I could be wrong!

Gary


2012 Plus 4 in Sport Green. Much comfier than the Plus 8!