[mr0077]

Johnny, this is kinda fundamental, but if it is consistently getting sideways in one direction, check the wheel alignment, particularly the rear end. That happened with my Shell Valley, every time violently sideways tail right, front left. I eyeballed down the sidewall of the left and right rear tires, and found the rear axle was rotated about 3 degrees to the right of the car centerline.
If that's not it, you may have to get into wheel preloads, etc. if you have a limited slip rear...maybe someone else can help with that.