Carbs over Cam

Hello,

I'm building 427ci small block chevy and it it has a Comp Cam XR300HR with the lobe centers at 113. (3000 > 7000 RPM with a REV kit) I have a tunnel ram with two Holley 0-4224 660 cfm carburetors that I plan on using.

I plan on running this motor on the street so I'm looking for input on the size of the carbs. I have found some new Holley 0-80507-1 390 cfm carburetors that might be a better choice. (780 cfm or 1320 cfm). Not only is the cfm lower but they have screw in air bleeds that will make the tunning a bunch simpler.

Any thoughts?

McGurk