Leafs Springs and Ride Height

Sorry if I'm beating a dead horse and someone posted this already!

Anyways, 2,800 lb leaf springs vs. 3,200 lb leafs...is 3,200 lb going to jack up the rear of my car significantly more then the 2,800 lb? Do I not know what I'm talking about at all? Someone school me! The leafs on my car now resemble a squiggly line and I have airshocks to help the load...btw...I'm looking at the leafs on Summit...http://www.summitracing.com/search/Make/DODGE/Model/DART/Year/1970/?keyword=leaf+springs

Thanks!!!
Craig