I am still struggling with the fact that if you set the traction bars up so they touch the springs all is good. If it was clutch chatter, how could setting up the bars affect that. I also go back to the fact that typically Mopar rear springs don't need traction bars just spring clamps. I hate to get fixated on something but this seems to indicate spring wind up. Too bad you don't have another set of springs, even lighter ones, just to see how it will react.
Spring wise though, I put a new set of Super Stock springs on it. It still shakes. Also all isn't good when the bars are set to the springs. That just makes the car bearable to drive. It still has some shake just not violent shake. Shook with my worn out stock springs too.
After doing all that to the rear of the car with the springs, pinion snubber and pinion angle. I believe it is up in that clutch area somewhere, especially since take off is good about 30% of the time. It's inconsistent.
