Riser block rear suspension???

[440 Smokin]

74 Cuda with a 440 and Tremec 5 speed. The car rides like a log wagon, especially the rear. Almost no give when you try to bounce the rear of the car. It has 6 leaf springs and for some reason an 1 3/4" riser block between the leaf springs and the axle bracket. KYB 554285 shocks. Not sure what the purpose of the riser is. Stiffen the suspension? Lower the stance? Rumor is it used to be a drag car, there are a couple of Mopar National window stickers on the front window.

So I want the car to ride better, more give in rear end. Willing to replace the springs and shocks. Maybe a premium adjustable shock like a QA1. Remove the risers? I like the stance of the car but would really like to get a decent ride and not have to inch over speed bumps anymore.

Any thoughts?

Thanks........