Fuel demand

Ok really wanting to run a mechanical pump. Question is what one will be enough. I'm coverting to a 3/8 sending unit and will have around 615 hp in my 512 cubic inch street car. Probably won't see full throttle pulls longer than 15 seconds. Can a stock pump handle it or would I need say a Carter, Hollet or a Eddy pump. No one has the Eddy pump which I like because it has 3/8 inlets and outlets.