Century GP7500E Natural Gas / Propane Conversion Kit Converts the GP7500E generator to Natural Gas / Low-Pressure Propane Additional parts sold separately to run on portable propane tank (Part Numbers:SEK-05A or SEK-05-12A) FOR SINGLE CYLINDER ENGINES ONLY Frame modification. The air cleaner will be pushed outwards about 1-1/4 and may interfere with the frame.