Hi
A 'Few'years ago I ended up putting a 3-bearing 2286 petrol engine from a Ser.11 landy into an early 110 without too many problems - my thought is that if an "old" engine will go on a "new" 'box, then it follows that the "new" engine will mate up to the "old" gearbox - does that make sense?
It should go - a mate has just put a 200tdi (from a disco, not defender) into a series without a great deal of aggro, except with the exhaust.
Hope it all works out if you decide to go for it!
chris