I know someone who has a 4.11 ratio rear end that will swap into your present rear end housing.
All a person has to do is drop the drive-line,pull the axle shafts outa little ways to clear the differential when it comes out.Drop in the differential unit and bolt it up.bolt the axles back in,fill it with gear oil(85-90W) and re-connect the driveline.
You will have to live with the speedo being off or locate a gear reduction for the speedo cable at the transmission.

There is enough good in the worst of us and enough bad in the best of us that it does not behoove any of us to criticize the rest of us.
-
-
Be yourself. If you are ever lost, It will be much easier to find yourself if you know who you are!