So I will first start by recognizing that most will doubt what is presented here so I will attach links to some videos from Huibert Mees. He is a renowned suspension engineer, who has done chassis designs for Ford, Tesla & others.
I refer back to my earlier post. Most think they know suspension, they think springs, struts, sway bars, (but never think of link ends) & maybe a few other things! And as such think they understand how to build a suspension. If the body rolls it must be springs or CG! So the first order of business; they lower the car’s CG by using a shorter spring! Terrible idea! Why? Even an inch or two down impacts the roll center negatively, while reducing the suspension travel!
I am not comparing myself to Huibert Mees, but I have designed suspensions among many other mechanical devices for more than 50 years & have many patents. So I’m not trying to garner accolades.
There are so many things to look at with a suspension, but if I pick just one thing to affect cornering & more specifically high speed cornering, it would be sway bars & their end link! Yet many ignore sway bars as a remedy. Even more so, most never consider their relative size vs end link size! If, I simply said to you, have you ever heard of Archimedes & his statement of "Give me a lever long enough and a fulcrum on which to place it, and I shall move the world." You most likely would say yes! Well to a degree this is your sway bar & end links! Do you honestly think a bar, aka lever, 4 feet or longer & ¾” or more in diameter; in some cases as much as 1 5/16”; can be effectively applied by a secondary lever that is more than 3x smaller!? In some cases like the solid aftermarket front bar of the W-body ll more than 4x smaller. If you did the section modulus of the two you would find the numbers even more staggering!
Amanita, without seeing your setup I would be guessing, but by your pictures several things appear to be part of the cause, but all point possibly to two issues. The sway bar & weight distribution. It has been many years since I have worked on one of the first gen W-bodies. So please correct me where I am wrong. Doesn’t the front bar end point attach into a u bracket & rubber bushing? Similar to how the bar attaches to both sides of the frame? If so, the bar as the rectification point! I can explain how. The second is the weight distribution. These cars, as most should know, have a horrible weight distribution. Again there are ways to affect this if you want to put in the work. Last the rear leaf. This can be improved, but it will take work & if you can’t do that work I doubt it is worth it to you to pay to have it done.
Last I will attach some pictures, sketches & links that may explain things better, especially the jacking force.
The picture of you car is presenting your jacking issue.