Not to ruffle any feathers, but I disagree that "Kohler really dropped the ball on this one". In my opinion, it is an awesome motor. True, it may be a higher maintenance motor, but if taken care of properly, it will last for a very long time. The tractor was used for over 30 years mowing, blowing snow, and plowing snow and the motor still works great!
I think you misunderstood Chris.... Kohler used the basic K341 16 hp block, and put an overhead valve head on it... this design has the crankcase breather on the side of the block, just about the same height as the crank centerline... I could see where it might cause a problem, but I don't think Chris was criticizing the whole engine.