:confused: I have a series-2 with the original Rover differentials and a series 3 gearbox. What are the revolutions of the engine at 110km/h or/and 100km/h?

I bought a Series IIA without its original gearbox, enjin and mountings. I have desided to fit a series III box but I have a problem in placing the box, the enjin mountings are already altered so I cant use the enjin for alignment. I want to use the original gearbox mounting brackets for it will...