Tex, If you are running 10% fuel try the APC 13x4w or APC 14x4 Standard chord prop mine was running in the 12600rpm range rich(ys20/20fuel) with the 14x4 std.....I didn't know it was running so fast, but when I tacked it I changed to the 14x4w...after a few more tanks I'll lean it out some more ....I didn't take pics of the tail feathers but there was allot of ice on the leading edge...... JW