Suspension & Brakes - rear moving at high speeds

The rear of the car moves from side to side really fast at high speeds. I mean really shakes from side to side. What will stop this. The car goes straight just that wobble. It got worse when I upgraded to the three way shocks set to firm.

I got that feeling when I broke my swaybar on the rear. It was worse in turns.

Are you running an adjustable panhard bar? If so are the jam nuts tight? Are the sway bar bushings and end links tight?

Are you running an adjustable panhard bar? If so are the jam nuts tight? Are the sway bar bushings and end links tight?

Yes I am. I will check to see if they are tight. I know the sway bar is but I didnt check the panhard.

The bar is tight. The only thing I can think of is that when I installed the shocks (first time doing so) I took off the worn decarbons, installed the shocks but didnt know how much to torque them down so I just torqued them until the rubber pinched a little and left it. This was done when the car was not loaded. These are three way adjustables and they are on the 50/50 setting. I did set that but I can now push the back of the car down and its bounces pretty easily. I thought firm would have made it harder to do but now when someone rides in the back it really bounces.

I'd start by making sure the wheels are straight and balanced.

My ride does the same thing. I'm more than convinced that my suspension isn't pushing weight down very well and causing a bunch of "dance" like you're talking about. Do I have a definitive answer? No. How sure are you that the springs and shocks are still good?

Find out what it was?

Yip believe it or not it went away when I got rid of those Pzero tires. Maybe one had a bubble? I couldnt see but who knows. All I know is with good rubber back there no more booty shake

Yea my rear tires are bad too, just got this car and the rear is moving around. Never had another fbody do this to me before though. Thanks.