I have read about head flow for years,But?????

[Warp Speed]

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[Warp Speed]

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[Abbottracingheads]

Airflow is not the be all end all in making power. You need air flow sure, but the runner size and shape and fuel handling is just as important.

[PackardV8]

Different inches of vacuum....heads are flowed at 28" and I believe a carb is flowed at only 10" or less.

IIRC, 4-bbl carbs are rated at 1.5 inches of vacuum and 2-bbls at 3".

[Carnut1]

Different inches of vacuum....heads are flowed at 28" and I believe a carb is flowed at only 10" or less.

IIRC, 4-bbl carbs are rated at 1.5 inches of vacuum and 2-bbls at 3".

What do they flow a single throttle body at? Thanks, Charlie

[cgarb]

I'm just saying that if you rated a carb at 28" the cfms would be a lot more than what they are rated at. What would the 300 cfm intake port flow at 1.5" of vacuum? The restriction is not at the carb because the intake isn't drawing all 8 cylinders at the same time. I didn't quite understand the point you were getting at regarding a 300cfm intake port and 800 cfm's at wide open. Not arguing I'm just trying to understand.

[modok]

Sinc he has a supercharger it should be real simple.
The runners are short enough you can just go by size. The carb needs to match the draw of the supercharger.

[MadBill]

Different inches of vacuum....heads are flowed at 28" and I believe a carb is flowed at only 10" or less.

IIRC, 4-bbl carbs are rated at 1.5 inches of vacuum and 2-bbls at 3".

What do they flow a single throttle body at? Thanks, Charlie

1 bbls carbs were also rated at 3.0" Hg.
EFI throttle bodies are a relatively recent development (compared to 1 or 2 bbls.) and with no fuel mixing duties, can be sized for less WOT restriction, so regardless of barrel count (3 on the 1990-95 Corvette ZR1...) an aftermarket manufacturer would almost certainly rate them at 1.5" Hg.(20.4 H2O).
OEMs? Who knows unless they list it...

[Stan Weiss]

Why does a port need to flow 300cfm, when the engine running full song doesn't pull 800 total?!?

Jay,
How much will that port flow in 3 Milliseconds?

Stan

[Warp Speed]

Why does a port need to flow 300cfm, when the engine running full song doesn't pull 800 total?!?

Jay,
How much will that port flow in 3 Milliseconds?

Stan

Kinda my point...........I think?!? Lol

[digger]

What's the size of the hole ...

[JohnsnsFord2@aol.com]

You need velocity

[user-23911]

The CFM that an engine consumes at X RPM is one thing.

The CFM that a head flows at a certain no of inches water is something completely different.

As is the no of CFM that a carburettor flows at x inches Hg,

3 completely different things with nothing in common apart from "CFM".

[barnym17]

Isn't the carb rated in inches of mercury vs cyl heads in inches of water (i.e. using manometer) the numbers would all have to be taken at the same depression, using the same measuring device to in any way correlate the cfm of the carb vs the port.

[barnym17]

Sorry I just saw Joe mentioned the same thing I did.