leaf springs

This has been cone on a number of "cars" over the years to increase load carrying capability without modifying the axle locating ability of the leaf spring. sometimes coil over shock absorbers are used to do this but the shocks themselves must be very good quiality & the damping rate appropriate for the spring rate. In the past I have used coils in the back end of leaf spring rally cars, you use 2-3 leaf's then add a coil. it reduces the amount of axle tramp and you can increase/decrease the spring rate quicker to suit conditions in a shorter period of time than having to pull the leaf's out and re-setup the rear end alignment all the time.
all leaf spring vehicals suffer this to some extent due to the long flat spring curling as torque is applied on a 4WD all four wheels get torque so you can get all four wheels "tramping" up and down on the spot!)
If you ever get to see an army jeep (yes the old ones!) with its leaf spring suspension & spring steel ladder chassis or for that matter an old landrover, dont laught they go places simply because they get to keep the wheels on the ground you will see what wheel articulation is all about.

happy motoring