I'd get a compatible shock from the same source of the front for the rear, ie another Stocker Star. If it were mine, I'd get a single adjustable so I could dial it up for street use and then dial it back for strip use.
No, mopars don't rock back in acceleration, they lift. The rear end should rise while stalling it in the lights, then when you let off the brake, the nose comes up to match. This is using the cars weight to leverage the tires into the pavement. If you have stock style Espos, the rise will be somewhat limited and the snubber, if the springs are working correctly, actually becomes ineffective unless you have a high stall convertor or four speed that is hitting the suspension hard at launch and twisting the springs.