I got some info on that SRD built 70 Camaro

[jannes_z-28]

3-link rear suspensions were the primary "thing" for ProStock cars in the 70s. If properly set up it would launch the car like a rocket. But the problem were just to set it up. The pictures of this one shows an early setup.

Later they started to make brackets for the upper rod to move the rod sideways. I have seen some cars that could move the rod 4" in sideway adjustments. Reason for this was that if the rod were not in the perfect side adjustment the car would launch in a twist, in extreme cases resulting in lifting the left rear tire. This made it really difficult to dial in the suspension on different track conditions and eventually they moved to 4-link setups that were more controllable even though they were not as good as a 3-link.

Jan