I run a holley 4412(500cfm 2v) on mine. I run high compression, big cam, big valves with header and 2.5" exhaust. The 4412 has been built to run on this motor, and it's still more than it really needs... mostly. Even the ess motors I've seen run the 4412. A 600cfm, with out a doubt, has more flow than the 2.3 could ever justify using. And down tuning a carb is just bad juju.
You'll want the 1", or so, manifold plate. For a few reasons, but mostly to help get the fuel mix into the cylinders in even quantities. And a low profile air cleaner.