I did a very similar thing.

1967 Charger 3800# Super stock springs relocated to the frame rails. CE shocks up front and C-body shocks out back.

The car ran mid elevens. I handled ok on the street, but I didn't like the way it sat or moved around under launch.

I mini tubbed the car and added CE Ladder bars with double adjustable QA1's at all corners. I also swapped 318 t bars in to replace the drag bars I had.

The added wheel room was great. The ability to adjust the rear ride height was also a nice feature.

The final result at the track was a quicker and more consistent launch a definite improvement of the leaf springs. A lot of this improvement can be attributed to the superior dampers.

It was just as difficult to move the springs inboard as it was to install the ladder bars.

This is a good way to go an a street strip car that doesn't see a lot of miles a year.

I was able to keep the interior and back seat functional, I'm not sure if that would be possible on a four link setup.

My only regret is that I bough QA1 instead of AFCO or Stanhuff for dampers. This change demonstrated to me how important good dampers are.

If exhaust clearacne is an issue using relocated super stock springs. I would think that ladder bars will have issues as well. Take a good look under there and decide what works better before you make a decision.