Rear suspension upgrades. 4 link?

[Dino]

I've been driving the car most of the time, except when there is snow on the road, and it's running really nice. The front alignment seems pretty good but I'll go over it again and play with the camber a bit more once it warms up. It tracks really nice doing 75-85. No issue there. But that rear suspension! It's always been rock hard. I sometimes feel like I'm driving a truck. It's unrelenting  and the crappy Michigan roads don't help. I have the, now discontinued, Edelbrock shocks, and the old stock leaf springs. Every rut or pothole makes the rear twitch, like the whole axle moves sideways an inch. The banging noise doesn't help either. No nothing is loose. If we had good roads this wouldn't be nearly as bad as it is, but this state has more potholes than potheads, and that's saying something.
Is anyone running a 4 link? I know they're not cheap, but if they could give me a more cushioned ride while maintaining good cornering manners, it might be the way to go.