Sorry I thought you were swaping a 4-runner with a pick up cab


The body mounts between an 84 4-runner and an 86 4-runner are the same length and width apart.  The only thing that would be a chalenge would be the wiring harness for the 86 motor.

I think you should SAS the 86, because it already has the motor, wireingm and wider rear axle.  All you have to do is SA.
Depnding on how big of a drop bracket for the springs hanger you use depends on how much lift you will have.  I have 2.5" square tube, 3" Tabs of that and the holes for hanging the springs are drilled 1" up from the bottom of the tabs.  So I have 4.5" of drop. With a 5 leaf pack I have about 4-5" of lift.  If you made you drop bracket shorter then you could probley get around 3-4", but you may have clearence issues with steering.  I made my drop brackets so far down so I will have more clearance for my steering, i want to have my bump stops set right before my spring s flaten out.