Drive Shaft Hitting

[69SS396]

I have stock heavy duty coils in the rear of my 69 and when riding around with two people in the car, the balance weights on the front of the drive shaft will hit the box floor reinforcement just behind the tailshaft of the Muncie. Not sure how to resolve this. Rear tranny mount is a stock, new replacement as are the rear coils. Ride height of rear is slightly low but seems similar to other stock 69's I have seen. Maybe I have the balancing weights moved rearward and the shaft rebalanced? Would be a good opportunity to replace U-joints and rear yoke? Car has had floor pan replaced, could they have done something wrong??

Ed