I finally found a drop out 4:10 rear end for my truck. I have been looking for a couple of years to replace my 4:56 locker ,I wanted to keep the locker but finding a 4:10 locker is next to impossible to find around this neck of the woods. I removed the drop out from my truck and took it to a local gear shop with my 4:10 drop out and they were able to put together a 4:10 locker using the best parts from both. My truck only has 38000 miles on it and gears and bearings were in excellent condition. This is a corporate axle with the Eaton gears in a 1962 gmc 920. I didn’t think it was possible to put the 4:10 gears on the locker and have it fit correctly. Something about the gear offset. I’m assuming it’s going to be hard now to find the correct speedo drive. Going to install this weekend and see how she goes.

1962 GMC 920 step side 261 4 spd