I disagree with most of the advice given. IMO, there are several different types of carbs being lumped together to make a larger choice seem "right" to a novice. The stock 440 did come with an 850cfm carb. But, that was dry flow rated which means it realy flowed about 780cfm when fuel is run in it too, plus the primaries were sized similarly to the throttle bores of the 600cfm Holleys, and the secondaries were entirely metered by a spring loaded plate that when set properly did not allow the engine to behave as an overcarbed engine. That system of controlling the secondary air flow, while done in different ways, is consistant with all Thermoquads, AVS, AFBs, all the Edelbrocks, and all the factory 6bbl setups Mopar offered. Again I'd remind you of the difference between dry and wet flow rated carbs, which is fairly drastic when trying to decide... So... My own opinion... If the engine is 100% stock, the dry flow rated carbs - the stock Thermoquad would be my 1st choice but they can be troublesome if you aren't used to them or yours is very tired; #2 is the oldschool 3310 series Holley 750cfm; #3 the 750 cfm Edelbrock Thunder AVS. For wet flowed carbs - the Holley 670 Street Avenger Vacuum secondary. You definately don't need or want a mechanical secondary, nor do you have the cam or valve springs to make use of the rpms where a larger carb would benefit you at all. In fact, the square bore design of the Holleys mentioned have the capacity to hurt idle quality and response because they are larger diameter.
