I have a 53 3/4 ton and I am using a 12 bolt Chevy truck rear end out of a 78. It is a 3:08 ratio, that I plan to change. But if you want to mount it under the springs of your truck (i.e. not dropping or lowering it), you do not even have to change the spring perches. Just move the 1/2" spacers at the spring eyes from outside the springs to the inside of the springs and that rear end will drop right in place. Use your original housing clamps, but buy some new 2" square bent u-bolts. This set-up will be a little wider than the 4x4 S10 rear. You can solve that problem by using the 3" wider rear fenders that are available or wheels with deeper backspacing.
