I have a 440 on my dyno now and have tested several carburetors on it. At 440 horsepower it was pulling 630 cam through the airflow meter. With a 650 carburetor it has a much nicer torque curve than with a larger carburetor. I have done similar tests on other engines and I can tell you with certainty a 600 will be fine. You may lose 5 horsepower at the very top of your rpm range over a larger carburetor but everywhere else will be much nicer.
Keith