"...You missed the word "if", I said IF you are over carbed with a 670 you will be over carbed with a 750 or 800."

Actually, here is what you posted, and the only reason I disagreed.

"...If you are over carbed with a Holley 670 you will be over carbed with a 750 or 800 CFM Rochester..."

Notice the word ROCHESTER, at the end of your sentence. I just assumed that you meant Q-jet. IF this is the case, then you would not necessarily be over carbed with a Q-jet, regardless of what cubic inch the engine is. If a 750cfm Q will work on a straight 6, and an 800cfm Q will work on a 301, then I see no reason why a properly rebuilt and tuned Q-jet can not work very well on a 350 engine, or anything else between 301 and 455.

That's one of the big advantages of the Q-jet. Properly tuned, they provide only the amount of fuel/air mixture the engine can handle. Obviously, this is not the case with Holley type carbs. Therefore their cfm must be matched to the size and intended use of the engine. Of course, as always, this is just my take on the subject, and I am not an expert, by any means. But, I have run 750 Q-jets on 350, 400, & 455 street and race engines, with good success. And there is a lot of online info that agrees with what I am saying.

But, there are a lot of Holley guys out there, who badmouth the Q-jet and always will. So be it.