Great little gray market tractor. Very easy to use. Heavier build than tractors of similar HP. Hard to find parts references. Belts and filters listed by most suppliers for this model don't fit, but not hard to find after I learned what to look for. Operator area is pretty cramped, but better after moving rear wheels and fenders out.
To give an idea of drawbar HP, this tractor can drag my Fred Cain subsoiler with only minor wheel-slip issues. I think some wheel weights will help a lot. Not bad for 18/15HP.
BTW - The tractor is a SD1500A0, not SD1643. I was not able to add SD1500A0 as a model.