You'd have to call Cass (Dr diff). He is the one who had them made, for HIM. He is the only source I know of. (There is also such a thing as a Dana 61, which has higher ratios than a 60 [3.08 etc. lower numerically]). A 61 will need to be modified with a narrowed housing ad non floater axle ends.I know this is old. But r 3.23 gears available for a Dana 60?