I had one years ago and may have some pics in the computer. The pulley for the drive belt was mounted to the back of the clutch between the main belt and crankcase. A sliding dog type clutch engaged the right angle drive to the pump. I believe it was a Berkeley Pump. It worked real good in open water , not great in grass.
You do realize that you will have to modify frame in order for pump to sit in the middle?They also used a 90 degree gear box between jet pump and engagement clutch then belt drive to a pulley behind the engine clutch. Phillips LA Osborn