anything but a 2.25. Go with a diesel.
Nothing wrong with a 2.25 petrol. Thats what my 75 station wagon has
I like the standard dsl but a 200 TDi will work great without the Turbo. I had one with a 200TDi and it just broke the rest of the car. A 200Di will have 80BHP and more torque than any standard motor along with having much better reliability. You can still use the Series Gearbox with this conversion which means you can still run it in 2WD. If you leave the 200TDi gearbox on you will be stuck in 4wd. Apparently its good to get the Defendwer box and not the Discovery box but I cant remember why ?