Quadrajet CFM Numbers
06-25-2003, 02:05 PM
#2
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Car: 4
Engine: 6
Transmission: 5
Same as almost any other Q-Jet, about 750 CFM or so, except that if it's a LG4 carb, it has this little metal tab that limits it to about 625 CFM that you can grind off, to allow the secondaries to open all the way, and make it bog worse if it isn't tuned right.
That's the wrong question to ask about a Q-Jet. Basically it doesn't apply. It's not like a Holley or something, where there are actually different carbs with differnt size bores and therefore different flow capacities.
That's the wrong question to ask about a Q-Jet. Basically it doesn't apply. It's not like a Holley or something, where there are actually different carbs with differnt size bores and therefore different flow capacities.
06-26-2003, 07:09 PM
#3
Supreme Member
Officially it's an 800 CFM carb since it uses the larger primary bores that bump up the CFM slightly over the old 750 CFM units. However, it is limited to about ~625 CFM due to the secondary air valve being limited to less than it's full 85-90* opening. Like RB said, grinding down the stop to get full opening will get you full airflow capability.
And don't be all freaked out about an 800 CFM carb on a little old small block- it'll work just great. The QJet's design basically eliminates the possibility of bogging due to over-carburetion, if properly tuned.
And don't be all freaked out about an 800 CFM carb on a little old small block- it'll work just great. The QJet's design basically eliminates the possibility of bogging due to over-carburetion, if properly tuned.
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