How much CFM for a 360?

Thanks guys for all the great input! O:)

Due to the fact that my current Edelbrock 600 doesn't have a choke setup on it (previous owner took it out), I have been leaning toward a 650 Speed Demon. Starting up that XE-274 cammed 360 in cold weather without a choke is a pain!

Any thoughts on the 650 Speed Demon vs the 670 Street Avenger?

Steve