Sadly, this is a common mistake that many have made. The MP XHD spring set is design to replicate the factory ride height specs with the additional ability to resist torque wrap delivered by big block engines. They are not designed to lif the rear of the car at all and when installed, will appear to be almost flat.
What many seem to forget is that when factory new, most E bodies looked droopy in the rear and it was only the addition of aftermarket wheels and tires that tended to create the rake that is so fondly remembered by most.
I'd recommned you add an extra leaf or two to your pack to get lift rather than use the air shocks. Air shocks have a tendancy to beat up the corssmember on anything less than smooth roads, however, so long as you aren't cranking the air up in the pressure in the shocks, they may not be as destructive.
