I put a 4/98 leyland in a 109 , had to fit an overdirve and 4.1 diffs top speed on the limiter was 66mph but would pull 2 ton up hill same speed.
Down side heavy lump, noisy due lack of soundproofing .
Very reliable , went all over europe, sold to a guy to go thru africa, as fitted with all the kit.

Suggest 300tdi best bang for buck as modifying vehicles for unusual engine fitment very expensive if done properly