Trans mount is new. The panhard bar is a UMI tubular one, shocks are new. The LCA's are level to the ground, not higher or lower. The passenger side control arm bushing at the frame is loose, the arm fell straight to the ground when the rear was pulled. The trans is coming out this winter to get pulled apart and inspected, rebuilt if needed. U-joints are good but an aluminum driveshaft is going in this winter too, and plan on Bilsteins all around. Would an adjustable torque arm be of any benefit, or adjustable LCA's? It's not a race car and it wouldn't be of any huge benefit to having the adjustability.

 

if funds are sort replace the lca bushings and see if that does it. if bushings dont do it then install the relocation brakets. lca should have at the least a little rise to it as it goes to the front of the car. rearend connection point should be a little lower than the connections point at the body. unless you need to move or adjust the rear then i see no reason to use adjustable lca's. the car lowered is a good reason to install adjustable torque bar and if you blowing trans mount use the cross bar mounted torque bar. if you are planning on beating poor sofie you may want to look at subframe connectors.

 

Stock V8’s do not have this issue if everything is in good shape. While your V6 is approaching V8 HP you have not reached the level of torque a V8 puts out(wheel hop is a torque issue). So in theory you stock rear suspension should be fine IF everything is in good working order. Anything with play it can cause the issue. Step one is to put a pry bar on everything and look for clearance.

The other thing I would check is the drive line angle. The angle at the rear pinion U-joint must be equal to the forward U-joint within a ½ of a degree. Most of the time when you lower or raise a car you screw these angles up. If you search Youtube you should find videos on how to check you drive line angle (AKA Driveshaft angles).

The symptoms of drive line angles not being equal is a slight vibration under heavy acceleration and deceleration. What is happening is one of the u-joint gets on a bind and works like a spring. It is hard on the U-joint but a newer joint can last for years as long as it is not too bad. You should feel it in the seat. It can be very slight I have driven car that the owners where so use to it they did not even realize there was an issue. GM does not acknowledge the wheel hop issue because they are kind of against people doing burn outs, but from my personal experience that any car with the drive line angles off will have some level of wheel hop, even on a brand new car. It could be that the LCA relocation kits address this issue. Measuring the angles can be kind of a pain because our cars are so low and you need to measure the angles with the car in its driving stance. I would tempted to just get the LCA Relocating kit.

Congrats on getting most of the bugs out of her. A lot of people would have thrown the towel in by now. Well done.

 

I'm looking into the relocation brackets now. Case went out to take a look. The rear does sit about an inch or so higher. So I'm thinking that might be the issue.

 

Yes that would be why, it's geometry with some torque thrown in for good measure. If you were to sketch it out, before and after, you'd see that in stock form with the rear of the arm mount lower than the front, any minimal rotating force would be pushing up on the bar at an angle. The way it is now, the rear of the bar is above center, and no longer has the angle to fight against. And worn bushings would only make it worse. Lowering the car is also going to drive the entire rearend back more, as the control arm levels out.

 

I didn't see this at first at the end, but thanks. I made several Facebook posts offering her for $5 at times. It's been frustrating, but I think she's good for at least a month (I hope) before something else breaks.