The difference between spring over and spring under can be nearly whatever you want it to be. Measure the distance from the spring pad to the axle tube, approximately double that, and then add the diameter of the axle tube. That is about how much lift you'd get by simply doing a spring-over-axle swap. You can change the amount of lift you gain going from spring under to spring over by getting taller or shorter spring perches. I think most spring over swaps tend to add between 4 and 6 inches, but like I said, they depend on the diameter of the axle tubes and the height of the spring perches you use.
Wagoneer springs seem to be a pretty good swap for Rangers. They worked well on Jey's rig.
2003 FX4 Level II. Twin Shifters. Black. A few mods here and there.
Originally Posted by SuperGildo@RRP
Kyle's a smart man.