Maybe this will help explain things
https://forums.maxperformanceinc.com...errerid=134156
Pontiac found the 850 Holley to make more power than the Q-jet on their SD-455 developmental engine that made more than 600 horsepower.
I'm sure as as heck not going to argue CFM rating but will say this as first hand knowledge and in no particular order
The Q-jet is a fantastic carburetor.
The 850 CFM Edelbrock carb flows more that an SD-455 carb on my flow bench.
The carb mentioned by the OP flows a ton more air than the 850 Edelbrock on my flow bench
The single ring booster and SD455 carb flow the same on my flow bench.
The 750 units flow less that the Buick Stage 1 carburetors
You increase the flow on a Q-jet and put it on a 700 HP Pontiac and it makes more power than it did before the additional air flow modifications.
You take an 800 horsepower engine and run a back to back test with a Dominator and a Q-jet and the Q-jet is going home black, blue and bloody.
You can twist numbers around all you want but at the end of the day you can't change the facts.