I just completed a 8" to 9" swap and the car now has what I consider seriously stiff rear suspension. During the rear swap I also changed all the leaf spring bushings which were fairly worn out or missing most of the rubber. Because of the change in how the vehicle now rides I began researching leaf springs and saw in a video featuring Eaton Suspension a representative of that company suggested the springs for an 8" and 9" are somehow different and when a rear is changed the springs should also be changed to match the new rear end. Normally I would be skeptical of this as it seems on the surface like a marketing ploy but there is such a noticeable difference in how the car rides I feel there may be some merit to changing the springs. With that in mind I wanted to see if anyone here has any experience or information that would either support or contradict the need for new leaf springs to match the new rear end. Thanks in advance.