[JoeC]

To adjust the pinion angle on a leaf spring car 4 deg wedge plates are used between the axle spring pad and the spring. Not sure if it is legal under pure stock rules.
Spring clamps are good for racing but not for driving on the street.
The early traction bars used a spring clamp on the forward end of the bar. I have a set of 1967 ET bars on my Camaro with the clamps. With these clamps bolted on it rode like a cement mixer. I removed the clamps and bolted rubber blocks in their place. Now they work more like modern traction bars.