RARE 3.91 gears (ring and pinion only) for AMC Model 20 rearend...Perfect for period correct upgrade, replace that 4.10 or 3.15!  (3.91 was factory ordered or dealer installed and has been discontinued a very long time and wont be made again - imo)...Look to be in very nice shape.  Sold in "as is" condition.  Please ask any/all questions PRIOR to bidding. Thank you.