I think you will need the 4.6 gearbox, if you obtain a 4.6 engine, as, I believe the box is a different lenght to the 4.0
A chap had a 4.6 litre car with a blown engine. I had a very low mileage 4 litre so he got that and his mechanis tried to fit it to his 4.6 gearbox - it didnt work as the...