My 94 classic 3.9 feels a bit vague at the rear around 70mph+ difficult to explain fully but it feels like the rear is not part of the rest of the car, Springs are changed, shocks are changed, both in the last 6 months it was rebushed about 2 years ago. My 84 3.5 is more stable at 70... any advice of where to look? Self leveller seems OK.. thanks Jon