Of course everybody has an opinion on carbs. Brands, sizes, secondary actuation, etc. And my opinion on this is that getting the right calibration is much more important than the size. As long as the size is not too far afield. Frankly, I don't feel that the CFM is the most important thing for a street car. A less than optimum CFM rating (within reason) would be less negative than improperly calibrated transitions. And less harmful in some cases.
Most here would probably agree that something in the 600 to 800 range would be appropriate for the OP's 440. But it is best to remember that each carb builder builds multiple versions of each size. In that 600 to 800 range there could easily be 60 or more different standard production carbs available. There are probably more than 25 750s alone.
And of course there are the guys that think that you have to spend thousands on some antiquated plug and pray EFI system. But a properly calibrated carb is very hard to beat for the bucks.
Most guys with mild street cars just want their cars to run good with the carb right out of the box. That can be a tall order and for many the reality is that it ends up coming down to luck. If the car runs good with a particular carb OOTB, it is a good carb. If there are driving or starting troubles OOTB, the carb is junk or it needs an expensive EFI installed to cure it.
In other words, it takes a lot more than getting the CFM in the ballpark for the car to start and run good without a lot of tuning.
As a short-cut, I'll make a recommendation based on my experience. The new Street Demons are the best out of the box carb I have ever installed on mild street engines. There are 2 sizes, 625 and 750 with the primary throttle bores being the difference in the 2. And there are 3 versions of each. The only difference between the 3 versions is the material and finish of the center sections. All come with an electric choke.
Either size will work okay for a 440 in my humble opinion. I would lean one way or the other with enough info on the combo and the driver's preferences, but either one should be okay for most mild street 440 combos. And the black composite center would be the best version. At only $300 or so, they are a bargain.
https://www.youtube.com/watch?v=oAhdCRixqqw
