re-arched springs, or stiffer ones--the standard height 5 leaf HD springs raised the back end of my M body about 1-1.5" over my well worn stock 4 leaf springs.

1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)