If you’re referring to that Indy headed motor making 700hp...... it’s “extremely unlikely” that motor was using almost 1100cfm.
On a more serious effort 572” build here....... the power output while using 1091cfm was 893hp.
The 572 street build that was similar to yours was using 959cfm@6100 while making 703hp with a Mighty Demon 850 carb.
Any air flow rating “number” is useless without knowing the test pressure.
Just like flowing a head at 28” h2o test pressure.
That doesn’t mean that’s all the air that can go through the head.
It just means that’s what it flows....... at that pressure.
If you flow it at a higher pressure....... then more air goes through it.
Same with a carb....... pull on it harder than 1.5” Hg...... it’ll pass more air.
My experience is that in most cases, unless there is a fairly high pressure drop across the carb...... there won’t be a real big difference in power from only reducing the pressure drop.
Example....... swapping from the Demon 850 to a Dominator 1150 on that street 572 was only worth 7hp...... some of which was from the 2” adapter on the intake instead of a 1/2” spacer.
However, on an 18* SBC Busch motor running the mandated 390cfm carb, pulling nearly 8” of vacuum at 8300rpm.......swapping to an HP950 would pick up around 100hp.
The air flow through the carb/motor goes up as the rpm goes up.
More rpm pulls on the carb harder, and the pressure differential goes up.
There is way less vacuum at WOT at 2000rpm than there is at 7000rpm....... yet the flow keeps going up(as the vacuum goes up).
The other thing to keep in mind is, it matters where you’re taking the reading.
If it’s near the throttle bores of the carb where the velocity is high, there can be some Venturi/siphon effect going on near the vacuum port...... inflating the numbers(over what the true manifold vacuum is).
As an example of bigger isn’t always better...... and that the quality of the mix is a big player in power output....... on a 452” bracket build I tested, where multiple carbs were tried, the biggest one didn’t make the most power, and the smallest one was arguably the best overall, including making more power than the biggest one.
If we are talking about that big Indy headed motor....... I thought during one of the tests a 1050/4500 carb was tried with no big changes in power.
One last thing....... if you do some digging you’ll see that the generally acknowledged “real world” flow rating for an original Holley HP950(80496) is 830cfm....... not 950.
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