Jose: The exterior dimensions of the O200 case and cylinders is the same as the C75/C85, so no modifications should be required. Some O200s have a vacuum pump below the prop flange, so a modification to accommodate that would be necessary.
The left front cylinder is mounted on the case closer to the front as the right piston rod comes second on the crankshaft. 5" sounds like a lot, though. Should be more like 2-3 inches. Also contributing to the illusion, the engine mount is canted 5 or so degrees to the right. (Left and right on an airplane are always specified from the pilot's perspective.) John Cooper Skyport Services www.skyportservices.net
