Here are the parts I have, what's the best approach?

Keep SBP. Easiest and the drums are available new, just need the backers. Your not gonna like that rear ratio. Is your 7.25 a SG? They are not that bad in a street car with a higher rear end ratio. Youd be suprised how a 7.25 SG handles a larger ratio rear (ie 3.55) under a light A. The 7.25 peg legs were underbuilt for a small block with a 4sp.