Need some help controlling body roll

You are right. I was made aware that it was not an original 340 car, when I purchased it. I accepted that because knew eventually down the line the engine was going to be messed with. I was not aware that it was a B-body rear. They told me it was a 8 3/4 rear, but foolishly I didn't think to question from what car. I guess when it comes to leaf springs, I need to get some that are an inch higher to clear the current wheels or will regular 340 springs work? The other option is to bring the wheels under the fender. If I get A body 340 leaf springs, would I need to change the shackles as well? These long shackles have a other mounting holes that are a few inches higher. They are a little close to the exhaust. I would prefer to get the wheels in under the fender. I would like to keep the rear height of the car right where it is.