Bill, You sould be able to find a fan in a yard out of a M2_M3. Early M2's had a sigle sprocket on lH side like yours and the later M2's and M3's had a double sprocket on lH side.Should be able to swap sprockets.Width and drive should be the same. As huskergleaner stated the head assy's. are loctited to shaft.New fans will have head assy's. clamped to shaft. Have been lucky to find a new style in the yards once in a while. There is a Worthington Ag. salvage yard in Evansville,WI.,(800-525-7278). Good luck. Hyper Harvest II