Hi Andrew,
The G Bodies have a four link rear suspension. Two upper control arms and two lower control arms. As you know these two sets of arms are of different lengths AND connect to the diff/axle at two completely different angles.
As the rear end moves the two sets of arms are moving at different arcs and this is worsened by the different lengths. This causes a bind in the movement of the rear suspension. Now this is not all that a big of a deal for a street car or even a drag car, it is a huge problem for a corner carving *g* machine.
Heim Joints are also called a spherical bearing. Instead of the standard bushings you see in almost all of the suspension applications which are basically a tube. Those bushings are just fine and will not fail any faster or slower than the heim. The 'tube' allows for free movement up and down BUT not side to side.
The heim is kinda like a ball joint that will allow for some articulation of the arm as it swings through it's path.
Confused? Me too!
In recent postings on the Buick boards most people want the heim joint thus my original statement.
