87 4Runner rear leaf springs

Hello All

So I have an 1987 IFS, 4runner that rides like a hard tail. I am trying to figure out why this is going on. The rear leafs look a little saggy but not too bad.
I want this thing to ride better but stay around the same height. Was thinking on replacing the rear leafs or shocks. Some nice adjustable shocks with a good ride would be great. I would like to keep the Rear end height between 13" and 13,3/4" Rear leafs are 3 leafs plus over loads.
The shocks are Explorer, Pro Comp, ES-3000.

I took some measurements and here they are.
Spring shackles (eye to eye) 6,1/2"
Rear Fender to top of rim is 13,3/4" (chrome trim on fender has been removed 15" rims)
Front Fender to top of rim is 13,1/4" (chrome trim on fender has been removed 15" rims)

 

Boogity boogity boogity
Did I post this in the wrong section? I do that a lot.