I was thinking about the problem with "bind" in the rear of our cars if you try to use urathane or other solid bushings in all locations. I have read most of the post on this issue... I think I have anyway.... and I was thinking this:
Has anyone tried a spherical bearing or rod end??
It seams that the problem is that the bushing will not "adjust" in the correct plane.... but a rod end/spherical would solve this problem.
The next issue, however, would be the harshness of the ride. Maybe a urathane bushing at the frame and a spherical at the Diff would be a good combo???
I mentioned this to a f*rd friend of mine and he was surprised no one made one for our cars... he said it's very common in the Mustang world... this is what I found:
Our new 3-piece poly-ball urethane bushing has a hard inner ball to prevent fore and aft movement, and softer outer ball cups to allow for proper angular rotation, which is necessary to prevent bushing bind. Our design is far superior to other 3 piece bushings with hard inner slivers, which causes corner break down during rotation of the lower control arm. This 3-piece poly-ball technology is standard on all our street and street/race mustang lower control arms.
Our spherical bushings are made of super strong 7075 billet aluminum, anodized bushing for less wear and a "teflon" coated com 12 bearing for maximum part life. These bushings will let your rear upper control arms and rear end move smoother and faster for more traction every time. Fits all 79-04 Mustangs.
This shot shows the adjustable uppers with a spherical rod end.