Holley 4779 750 cfm Double Pumper

Bewy said

HSDemon.
News flash for you. Every carb, Holleys, QJs, Carters, Edel etc all have plenty of fuel from the idle cct for a rich idle.
The idle cct jetting is not sized for idle, it is sized for transition; transition to the main cct.
Transition requires MORE fuel because more air is entering the engine. The idle & transition cct are all part of the idle cct & connected by internal passages. The problem then becomes how to reduce the fuel to the idle port because it needs less fuel. That is what the idle mixture screws do, regulate the fuel+air for engine idle. There is always enough idle fuel provided the throttle blades are correctly positioned in the bore, ie about 0.020-0.040" of T slot showing below the blades at idle.

Click to expand...

I have no idea why people that have no clue what they are saying state such easily debunked dribble. Here is a photo from the book written by Cliff Ruggles on how to modify Rochester Carburetors for high performance use. Book is called

How to Rebuild & Modify Rochester Quadrajet Carburetors (S-a Design)​

Cliff literally wrote the book, and he is considered one of the top guys that has ever worked with a Quadrajet. He, not me out of my personal experience, clearly states that the Rochester Carbs have limited idle fuel capabilities and to correct them you need to enlarge certain passages in the in the carburetor (ie drill them out).

Here is a link from his website on dealing with lean conditions of Rochester Qjets, and if you look you will find a ton of threads of people having the same issue:

Lean Idle solutions?