I have 3.23s with a 9.5 inch SMR converter in my small block challenger, the 3500 stall speed is a little high with the 3.23s on the freeway. It flashes back and forth. I am going to rebuild my spare sure grip chunk with 3.91s. I just don't think going to 3.55s would be worth it. I'd go lower. Maybe 3.73s