[Sam Mac]

This is doable but it will be challenging. It will definitely require a custom adapter between the engine and the clutch. I agree that the PTO needs to be your starting point and then work to the rear from that point. What I would do is to locate the engine for the proper PTO location, then I would get the angle and alignment for the drive shaft worked out you need a straight line from the input to the trans all the way through the engine. Think one solid shaft connected to the trans ending at the PTO. Once you have that worked out then you can get the measurements to make the spacer that will bolt to the engine and the 3 pin driver for the clutch. If memory serves the B&S had an odd ball 3 pin driver so since you are going through the trouble if it was me I'd try to design the adapter to accept something that fits a Kohler. Try to keep the one off stuff to a minimum. Hope you have a good machine shop because you will need it. Hope this makes sense.