The OHV11-13 engines are a 21.82ci displacement, 2.532" stroke, and a 3.312" bore. They are smaller than the 29.9ci OHV135-180 engines. They have a different rod journal size and length. I do not know of any performance stuff for these engines.
You could take out the balancer, provided you plug the holes so it retains oil pressure. The chances of it living that way? I would say, with a stock rod and off the governor, none.