Inline sixes are inherently balanced, so the "different stroke" idea doesn't hold water. 235's from 1941 to 1953 ran the same balancer as a 216. Six cylinders including 216, 235, 194, 230, and 250 all have the same diameter crankshaft snout (1 1/4") as well as most small block Chevy V8's. All the balancers for those engines will press fit onto a stovebolt crankshaft, but they won't necessarily have belt grooves that line up properly. Some have bolt-on pulleys.
Jerry
