83 110 engine question

[Roverlab]

I have a customer with an 83 110, 3.5 and a 4 spd. The engine has developed a loud unpleasent sound deep within the bowels, and the 3 bearing caps we've removed are down to the babbit.
We've been discussing various options along the lines of rebuild, repower, auto conversion etc., and one question I'm not sure of the answer:
Will a 3.9/4.2 distributor engine from a 90-94 RRC bolt up to the original 4 spd?

Thanks!

Trevor

[solihull109]

PM sent