Raise rear end with extra leafs??

I want to get the rear end of my 64 Dart up a couple inches for tire clearance and attitude but cannot afford SS springs at the moment. I do have an extra set of used stock springs, can I add a lead or two to the set already on the car and will this raise the rear any or just cause problems? Car has an A-body 8 3/4 under it now with air shocks to keep it up. Running 245/60/14 tires on 14x8 rims with unknown b/s. If the wheels had another 1/2" - 3/4" of b/s they would fit in the wheel well but changing rims is not an option, plus they are vintage SBP slot mags so I want to keep them. Also I like the 70's / 80's look of the jacked up rear. I considered lift shackles also but don't really want to go there either.
Thanks!
-Tim