Mancini has a rear spring front hanger and backing plate, which will allow you to raise the spring, in the front, @ an inch, which will lower the rear end of the car.
Super Stock springs are stiffer than stock springs. I run a pair of 2800 lbs passenger side Super Stock springs on both my 3700lbs A-Body convertible and on my similar weight E-Body. The extra weight of the car really tames the ride harshness to the point of being firm yet comfortable and compliant. It also helps obtain a nice ride height.
Lubricating the attaching points of the rear suspension makes a noticible difference in ride quality and road compliance too. For optimum ride quality, lubricating the spring and shock bushings with a synthetic grease such as synthetic disc brake lube, which doesn't attack the rubber or poly bushings is crucial. It allows for a much more compliant and smooth ride.
