Adjustable spring plates
 

I'm trying to raise the rear of the car 1/2". I should be able to turn the eccentric bolt to do this, but when I loose both bolts and turn the eccentric bolt, the plate labeled "B" creates a gap at the retaining bolt and doesn't seem to change the angle of plate labeled "A". Am I missing something here?
https://ibb.co/VLPdrGv
https://ibb.co/VLPdrGv

That gap means you’re moving A down with respect to B which raise the car. The question is whether that adjuster will have enough range to raise 1/2”

The marking on B starts in the middle of the markings on A. When the marking is in the position shown, there's no change in the angle of the spring plate (as measured with a gauge) and the only thing that appeared to move was B. Maybe that's how it's supposed to be? I was expecting that plate A moves to change the angle gauge, but that plate B wouldn't create a gap at the holding bolt.

Is the car on a lift or sitting on its wheels? If on a lift A can’t move since it’s fully extended against the shock but you’ve increased the spring tension.
If it’s on the ground you will have raised the car.

Edit - ignore me, I was looking at the wrong bolts.

The adjustments at the spring plate are intended to change alignment settings, not change ride height. To change ride height, you need to clock the torsion bars relative to the suspension.

The car is sitting on a jack at the torsion bar cover."can't move since it's fully extended against the shock" makes sense to me, but I'm not sure how to actually gain the adjustment if the locking bolt is moving within its hole on the plates.

If you remove the shock and the 1 bolt off the spring plate you can get the plate to go further down. When satisfied with adjusting you can jack up the trailing arm to get the shock reattached and the spring plate bolt back in. By doing so you are preloading the rate which will effectively make your car higher.

Thanks for the suggestion! And by the way, this is how it was done to get the 1/2" gain in height that I needed.