'Note the similarities between these three engines: From left sits an Alamo, a Rock Island and an Empire gas engine, all built by the Alamo Mfg. Co., Hillsdale, Mich. According to CH. Wendel’s American Gasoline Engines Since 1872, “(Alamo) Blue Line engines of 2 HP were of somewhat different design than the little 1 HP size. The cylinder and water hopper were cast in a single piece with the cylinder bolting to the frame.” Looking closely, you can see the Alamo and Empire engines share the same base, but the Rock Island features the one-piece casting Wendel wrote about. '