Rather than doing a regular quote and comment I'll break it down for each thing. Hope it helps a little.
"The weights were done with me in the driver seat. I do have noted that the weight percentage on the rear is 44.2 percent."
That's good but you also need to do it when you're out of the car. This will give you an idea of how your body weight affects the car. Think of yourself as a movable weight. You also need to remember that most of the RWD GM cars come up light on the right rear. When a pegleg takes off the right rear is the one that spins so that's not unsual.
" The left front shows signs of a front end accident. The alignment shop confirms that the left front of the car frame is bent. No idea how much. The corner weights show that the left front and the right rear is light."
Did they at least say which way it was bent? I can tell you a cheap way to straighten it but you need a concrete pad a little bigger that the cars wheel base and 6 mobil trailer anchors. If you get the scales you put them under the wheels to get a weight, then remove them and with chains and a come along you can pull to get the car straight. just remember that when you pull her relax it and scale it until you get the weights right.
"With the higher percentage of the weight on the front, if the left front spring was lighter or the overall left corner of the car was higher in relation to the other corners, the car would dip down at the left front and lift higher in the rear, taking weight off the right rear."
Well as I said, for some reason most of the GM RWD line always came up light on the RR. Now with the twisting action of a launch it gets even worse. The weight transfer isn't ideal but this is going to sound funny. Have you ever been to a dirt track Don? If not you need to go and look at some of the stock body class cars. You'll see a few of them being able to pull the left front off the ground in a straight. Even some of the bomber clases can do it and they have to have the engine in the factory location. These guys have the car scaled to get the most out of weight transfer and the guy that does the work is very familuar with what springs and how much weight to place where.
"This is exactly what appears to be happening with my car.
The left front riding height is lower than the right front, and the right rear riding height is higher than the left rear. So the car is basically rocking back and forth between the right front and the left rear corners."
Well it really sounds like the chasis is twisted and that would account for the weight being different on the LF and RR. If you do the frame straightening idea you can use a floor jack under the frame to lift which corner you need to pull down and fix the issue. Kinda like a taffy pull I know but it does work.
"The easiest way to correct this is to reduce the right front spring strength to drop the right front corner to the point that both front tires are scaling the same. This will automatically drop the right rear corner and increase the scale weight on that tire also."
If you do it this way and the chasis is twisted you can get it to ride level but when you launch it's going to want to change directions as soon as you launch and max effort will be in the wrong direction.
"By me using the spring clamp, I basically tested this theory and the riding heights at the corners followed my thinking. As I clamped the spring down at the right front, of course, the right front dropped down."
One other thing you might try is to switch the front springs. If you're using a "factory" front spring set most of them have a right and a left spring. The drivers side has just a little more power to compensate for the driver. GM realized most cars will have only 1 driver in them most of the time so the LF spring will either be slightly longer or be just a little stronger.
" Also, the left front dropped some, since now the left front was being asked to carry more of its share of the front end weight. Also, the right rear corner dropped. Where before the clamp the right side ride heights were 1/2" higher front and back, after clamping the right front spring, both the right front and rear are now 1/8" higher than the left. I stopped at this point, realizing that I had to clamp the spring a bunch to get to this point, and that it would probably be best to start cutting some of the spring off."
Don't cut the spring.
If you do it will have a different rate and change the handling charateristics of the car. Weigh the car first, mark the springs as to where on the car they are, and then take the springs to a dirt track chasis shop to see what the rates are currently (they have spring rate checkers). You may find the rates are reversed. Done it myself a few times so it does happen. Also take your weight measurements with you and see if they will give you a better idea of how to set up for straight. Most of them do it but don't advertise. A guy that knows how to properly scale a car and set your percentages is worth his weight in gold.
