Century Fuel Products Honda GX390 Natural Gas/Propane Conversion Kit for Side Mounted Air Cleaner Run on natural gas, low pressure propane or gasoline For Side Mounted Air Cleaner Engines Only Additional parts sold separately to run on portable propane tank (Part Numbers:SEK-05A or SEK-05-12A) We are unsure if you need to cut the frame. The air cleaner will be pushed outwards about 1-1/4. This kit is only for the HONDA GX390.