Try a Holley 770 or 870 Street Avenger. It's built for the street. Or, look around on the 'bay you will find 850 vac secondary carbs that come stock on bigblock chevy crate motors.

BUT.....

Hey, wait a minute! Back in the '70s there was one of the hot rod mail order places selling brand new 800cfm Holley spreadbores for $59.95. I bought two. One went on my brother's '67GTO and I didn't have a use for the other one. A freind bought a '73Coupe DeVille and didn't like the performance. I sold him the other 800, bolted it on and the car came to life. It had a lot more snap thrououht the whole rpm range.
Engine displacement - 472
Carb number - 6213

If you are running a spreadbore intake it's a no-brainer.

R.