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Old 12-29-2005, 12:09 PM   #1
C10 - C90 Bill
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Carb CFM Info Needed

Trying to find out the CFM difference between a Rochester 2-Barrel on a 307 compared to a Rochester 2-Barrel on a 350. This is for my '72 C-10. Any info would be appreciated.
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Old 12-29-2005, 01:42 PM   #2
farside847
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Re: Carb CFM Info Needed

Yeah Id be interested to know too, I have the rochester 2g on my 307 - I have never known its rating....
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Old 12-30-2005, 10:16 PM   #3
C10 - C90 Bill
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Re: Carb CFM Info Needed

Guesses are also welcome.
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Old 01-02-2006, 12:42 PM   #4
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Re: Carb CFM Info Needed

Ah, one of the great mysteries of the universe...
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Old 01-02-2006, 07:49 PM   #5
C10 - C90 Bill
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Re: Carb CFM Info Needed

Quote:
Originally Posted by farside847
Ah, one of the great mysteries of the universe...
Yeah, It looks like no one knows much about the lowly 2-Barrel, but I'm glad I got mine for the gas milege.

In the meantime I was talking to National Carb down in FL and his opinion was that there wasn't much if any difference between the two.

If I do find out the exact or approx CFM, I'll let you know.

Bill
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Old 01-02-2006, 11:14 PM   #6
Don Smith
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Re: Carb CFM Info Needed

According to my info :
1 3/32 in. venturi cfm is 278
1 3/16 venturi 352
1 1/4 venturi 381
1 5/16 venturi 423
1 3/8 venturi 435
could use any of these on any V8
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Old 01-02-2006, 11:52 PM   #7
C10 - C90 Bill
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Re: Carb CFM Info Needed

Appreciate the info Don.
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Old 01-03-2006, 12:29 AM   #8
jimfulco
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Re: Carb CFM Info Needed

If you're going to compare them to a 4-bbl carb, don't forget that 2-bbl carbs are rated at twice the pressure drop (suction) as 4-bbls, so you have to multiply the 2-bbl rating by 0.707 to get a figure that compares to a 4-bbl's rating.
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