Jezmo: I think I am going to try the .90 Tiger with a 20-1 mix using the Pennziol. I have read that more oil = more power to a extent. I am not worried about the small mess on aircraft. It is a good Idea to clean them off anyway and check fittings. I Have read about the needle bearings Ken has installed. That was very nice of him to share data and photos of the process. Not many people would take the time & effort he did. I got to get a little more handy with my Lathe and Mill to try the needle bearings right now. Also I am working on a Holt 4 cylinder stationery engine. Best regards, Capt,n