Originally Posted by gow589
That's called a Watts Linkage.
And it's way over complicated for 9 out of 10 applications it is used on. Putting all the lateral side loads through the bolts that hold the rear differentail cover on seems quite silly, IMO. Not to mention the example shown above uses heim joints, which transmit all the suspension road noise from the suspension right up into the frame and into the vehicle.
Unless your building a road race truck, keep it simple. And even if you are, NASCAR uses a copy of our truck arms, the same basic set-up used on '63 thru 72 trucks.