Hi That is a old MRP gearbox. They most often came in their Hydro boats and one of their Cats. With the orginal gears you got 1to 1 ratio but, with two motors. If Simon is right about the gear tooth count 30 pinion and 70 spur ,you will have 2.33 to 1 ratio . Thats a real high ratio for fast boats but can work. You will need hi reving motors to get it going . I have a couple of these Mrp gearboxes. One is for sale cheap. n.h.schmidt