The rear wheels can push directly on the frame when connected, instead of the sheet metal floor being part of the 'push'.
As the rear frame rails are solidly welded to the rear of the body assembly, the leaf spring bushings are the component that absorb the forces of road vibration and drivetrain action. The subframe connectors do very little, if anything, to affect the rear suspension. What they do is help prevent the body from twisting, or in the case of convertibles, sagging as well.
I disagree. The differential pushes on the leaf springs. The springs push on the front spring perch. The front perch fastens directly to the connector. The other end of the connector pushes on the subframe. This 'bridges the gap' between spring and frame. The engine rattles the subframe. The subframe mounts isolate the vibration to some extent. This is basic car body design. If you elimanate the bushings with solid metal you change the basic design. IMO Solid bushings are for all out race cars only... You will never get the ride that an 'isolator' will give you with solid metal bushings...
