Need some help controlling body roll

Demonracer and Oldmanmopar, thank you. What would be the appropriate wheels for the car? As for the shackles/leaf spring debacle, I know nothing about them, but I am willing to learn. I will order a stock setup and do away with whatever is underneath the car. The rear end is a 8 3/4 the car started life witha 318 and whatever came with them back then. It now has a 340 (verified off of the block) Obviously one of the previous owners decided to change some things. They didn't leave a guide or receipts for what they changed out.