I still need to check engine RPM. Analog tach in cab shows 2450, but they have been known to lie. Engine does sometimes pull down to 2350 under load. Metal curtain is up. Cylinder beater driver sprocket is 25 tooth, driving 18 tooth on beater. I run at the low end of cylinder rpms when I can, 5-600, so would upgrading to a 30 or 35 tooth driver be advisableIJ Fan belt is newish and tight (spring in front hole). Have channel concave on door. High profile concave appears to be angle iron. What are the dimensionsIJ Are the OEM concaves heat treated or will most any machine shop have what I needIJ What are the chaffer and raddle levelers you refer toIJ I don't find any reference to them in the parts book.