For sale is an excellent Winters #8510 quick change gear set with 17 and 23 teeth.  This is set 10 and in a 4.11 ring and pinion rear end this yields a final ratio of 5.57 and in a 4.86 ring and pinion rear this yields a final ratio of 6.57.  This is a 10 spline gear and very nice.  Thanks for looking and as always I combine shipping when possible.