RE: Help to ID OS Cylinder Head ?
It looks like a heli or RC Car cylinder head. Without seeing the actual engine, though, it's not possible to determine if it's an O.S. part or a part for another brand of engine. It's not possible to determine the engine's displacement from the picture. The diameter of the round part that sticks up will give a clue to the engine size, but still, not enough to identify which engine that part came from.