By the look of your line up of cars, I presume you're talking about an early B-body. I had the same issues as you have but I did not want to go to a smaller side wall tire because I need every thing I can get on the ground patch.
So what was my remedy? Doctor Diffs bolt on inboard kit. High quality made kit by the Doctor himself. The only welding needed was the spring perches needing to move in only a half inch or so and this whole set up gave me the 1" clearance on each side.