The 409 had three different HP ratings with different 4-barrel carbs.
(1) base engine had a single Rochester 4-GC
(2) middle engine has a single Carter AFB
(3) high-output engine had two Carter AFB's
Quote Jerry (Hot Rod Lincoln) "Edelbrock carbs are poor-quality imitations of the Carter AFB".
Jerry is being too kind to the e-clone; they really aren't good enough to be called a poor-quality imitation. I would rather try to make a double log manifold and eight Rochester B's work than the clone! The clones are permanently banned from our shop.
Jon.