uneven rear

[Hank70SS]

Frame height is pretty much determined by the suspension, axle, tires, springs. If you've changed springs I can't see the frame being off that much although anything is possible. Have you measured from frame to ground while sitting on a level surface? Is the frame off that much or is it the body that is off? Have you measured body, floor pan, trunk pan, distance to the frame? Have the body bushings been changed?

Lots of questions, I know, just some things to think about.