Move the engine back. Or would it be possible to move the radiator forward and possibly down so it goes under the top frame work on the core support?
Another possibility, did GM make a serpentine system that would fit your BB and fit the subframe? If so, you could detail it like Nathan did with his LS3. I thought he did a fantastic job making factory brackets look great. That may not extend out as much as the front runner system
If you say screw it and go LSx, you don't need anything more than a single pass radiator. I'd stay with the BB though just because you already have it and they are cool to look at when you open the hood
