[RA6T7GTO]

hope somebody has a good idea, my 66 lemans develops a wobble at 40 mph, i can see rear view mirror shaking and can feel it in the floor at my feet.i feel it a little at slow speeds but 40mph is where you feel it the most,i changed my wheel and tire combo, had tire rebalanced 2 times already,i put in new springs and shocks in the rear and still no change.front end isnt too bad, one balljoint has a little play but i dont think it would effect the ride,any help would be great, thank you