Hi, thanks. I guess I could calculate the final drive to know for sure. I know the picture isn't very clear but the number is definitely 9947051. Obviously corrosion has been eating it away. I don't think there is a letter in front of it, which is a surprise. I suppose the corrosion could have taken it completely. As it is an F2 serial number engine, so say 1970 (1300 SP), what gearbox would it be if original?