3.23 gears and speedo cable

3.23's aren't real popular in the aftermarket but you see used ones advertised quite a bit. What rearend? If you have a 8-3/4 I bet someone would gladly trade you straight across their 3.23 3rd member for your 3.91's.

Change the adapter in the trans. to the older style. It's a direct bolt in. The only thing you have to watch about is matching up the right gear for the speedometer to be accurate and getting it clocked right in the trans. The gear slips into the back of the adapter.