School me: 63-66 Dart vs 67-72 Dart suspension

As far as I can tell there is no real way to easily laterally locate a leaf sprung rear axle, like you can do with a 4 link(6 in the qa1's case). This backs up driving impressions of my first car, which was a 69 Valiant. I could actually feel the tail of it shift slightly under cornering. The front suspension on any A body is already designed well so that's not as much of a concern as the rear.

Looks like it's roughly a 2 inch difference in rear axle width. That doesn't seem like it would be too much of a concern.