LT95 with NA 2.5 in 109"

I've just bought a Series 3 LWB that is good in the body and really sound chassis. It's got the original 2.25 diesel but with bits of the engine dismantled and in the vehicle. I don't know what the gearbox is like as I can't tell without pulling it apart or getting the engine running. I've got a low mileage LT95 out of an ex-govt V8 110 with an unbelievably quiet overdrive and a choice of 200tdi, 300tdi or na 2.5 motors. Has anyone made this combination work, or any details that could be useful? It's a left-hand drive which may make any turbo equipped motor a little more difficult. I'd like to bore out one of the NA 2.5, or am I looking for power that just isn't available? Thanks in anticipation. ?.......