More carb, more power, more mph. A lot of engines will pick up from a 4500 carb over a 4150 even at the same cfm. Have seen a few cars cut up to .3 just by going to a dominator (obviously tuning it to their combos) one thing we know about small block mopars is that they love to have a lot of carburetor. Add in more cubic inch and big heads and I am sure it would see a significant improvement. Good luck, send me $10 when you get in the .40's LOL