Dual 500 cfm carbs can easily support 625 hp. I'd use the smaller carbs for something that is going to be street driven. You can go with 750 or 800 cfm carbs if you want. The air valve secondary is pretty forgiving in terms of over carbing an engine.
If they actually flowed 500cfm....Those eddy 500's only flow 350cfm or there abouts. I would run 750 or bigger manual eddy carbs with all the choke stuff removed.
