Carb CFM.. Increase?

It is setup like a track car but will mainly be driven on the street. It is in a 72 Duster and it does not get driven much so I was not concerned with it being what people generally consider nicely streetable. Hughes 3500 10.25 converter, 4.30 gears 27" tall tires and it will have 28" when it does go to the track, I expect the engine to make at least 550. I certainly know the 650 would be a restrictor plate on it. I think 850 probably would be about right.