A Holley 4150 @ 700 or 750 CFM would be a better choice. (Part # 0-4778 & 0-4779)
The carbs are set up to run rich at part throttle. For street use, you want to enlarge the Power Valve Circuit Restrictions. That will bring the part throttle mixture back where it should be.
Since you don't sound like you know your way around Holley carbs, I would suggest you buy the carb from the Carb Shop or somewhere similar and let them set the carb up for you.
The Carb Shop
Also get yourself a book on Holley carbs and learn something about tuning them. I would recommend:
Amazon.com: Holley Carburetors (S-a Design): Dave Emanuel: Books
Kevin