Only while changing lanes?
If this occurs only while changing lanes, I'd be more apt to blame driving habits (quick movement vs slow and smooth lane change) or tires... Sometimes the tires can 'grab' the road surface, I know mine do and I am careful on rutted and 'pitted' roads or changing surfaces, and especially in the rain.
My 78 has the gymkhana suspension, also.
Now if you are feeling a 'sway' when accelerating or decelerating, this could be an indication of another problem, the causes of which I THINK are worn yokes or suspension.
I am sure another more experienced member will chime in soon.
Heidi