I think you would be awfully close to the spring doing this. I run 5.25 BS with an 8" wheel, but have offset hangers and shackles which move the spring inboard 1/2".
At one time, I had 15x8 with 245 60r15, and 4.5" BS on my 69 Dart. Going by memory, but I believe I had 3/8" to the springs, springs in stock location at time. The 245's rubbed on the wheel lip on passenger side.
