>all quadra-jets of this time were 750 cfm< (Even if it were an 850, it wouldn't matter.)

That’s available cfm. Many people don’t understand how quadrajets work because it’s physically impossible for a quadrajet to be too big of a carb for any engine.

I’ve retired from technical conversation, an occasional consultant at best, so I’m not going tech on the subject. Overall function: The quad is a self regulating fuel delivery system. Engine demand, not throttle plate position, determines fuel/cfm delivery; simply, if the engine is only able to intake 350 cfm of air, the quad will limit airflow 350 cfm. And if you understand how they work, they will bring out the best of any engine that is able to consume 750/850 cfm of air.