Took my 81 to the track with the new turbo LS for the first time for some testing last week. We weren't leaving under any power or boost just rolling out of the hole to make sure all the fuel tables look good all the way through the trap. All the passes went without issue and we got the tune all lined out for this coming weekend. The only thing I noticed was as soon as I crossed the stripe and let off I would get an awful cyclical vibration in the car, and even on the brakes. I know bad pinion angle can cause a vibe like this. So my thought is under power the pinion is wrapping up to good position and then on deceleration the axle unloads and the slide-a-links(the slide-a-links are a two piece bar design with a poly bushing in between) seperate and the pinion is dropping to far nose down? What would you guys do? I have some 1.25 DOM/.120 wall in the garage so I could build a solid bar. Thoughts?