If I recall correctly, I had the lightest springs (2800)in my Dart way back when, and the wheelbase was moved forward 6 inches as well. It had a lot of rise, probably running out of shock length even with the long shocks.
Just an opinion, but I figure the more rise the better on both ends for a street car if you want max traction. The picture is of my Dart running low tens, way back when!