when i add my add a leaf i want it to raise my blazer, but the leafs go under the axle, so if i put it on will it drop my rear 1-2" from making it stiffer?

 

an add a leaf increases the spring rate of your rear springs. That causes the rear of the vehicle to lift up as well as give you a stiffer ride. the only way it would drop the suspension would be if you installed it upside down on the top of the leaf spring...please don't.