Fuzzy Math

Yes, but...
Both the Six Pack and TQ used vacuum operated secondaries (in the case of the TQ, the air valve was vacuum operated) So the engine doesn't flow more cfm than needed at any particular RPM range. The DP Holleys use mechanical secondaries so "over-carbing" can become a very real issue.
Just another reason that the old "cfm formula" can get thrown out the window. It is just a generalization, anyway.
Heck, @318willrun is running a 1200 cfm dual quad on a mild 318.