get me a pic of the rear end housing, If its a control arm like the chevelles were then its a upper control arm bushing for either right or left rear.

The gear ratio thing I know by counting how many times the tire rotates to the rotation of the drive shaft or yoke if no DS is hooked up.
Mark the tire and body, then mark the diff housing and the yoke, easier to count this way.

So for every 3 full rotations of the tire, the yoke should spin 23 full rotations as well. ratio = 3.23 as an example.