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CFM ratings for webers

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NQRS
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2015/10/02 22:55:07 (permalink)
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CFM ratings for webers

Hi All,
 
General question- has anyone published/ listed CFM ratings for the various webers. Know there are variations with choke- venturi sizes. Reason for asking- recently changed my twin 45's for a  Holley. Didn't honestly expect, when my brother brought it up for me from Bris, that it would be a 350. I have had mates fit these on 3 litre six cyl engines and my first thought was it would over fuel the engine. However it came off a 2llt Pinto which is only a bit higher spec than mine and it worked well up to 8000 revs. Idles and runs well and pulls hard.
 
Cheers,
Len
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    RSman4ever
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    Re: CFM ratings for webers 2015/10/03 08:01:38 (permalink)
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    I knew of a Toyota starlet rallycross car with a pinto,350 Holley setup, worked well but it was an absolute screamer I doubt it would have made a very good road car engine
    #2
    martymexico
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    Re: CFM ratings for webers 2015/10/03 10:26:11 (permalink)
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    A 350 holley is a mm or two bigger than a 40dfa weber . Yu will get better lower rev performance than the twin 45s ... Not to mention economy.. If that matters.
    I personally don't like holley carbs after i had a 4barel 465 on a pinto (only cause i got a esslinger intake cheap thru quickco) and ran it for a few months until it set the engine bay on fire ! I would fit a 38dgas or 40dfa ..
    #3

    Flighter
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    Re: CFM ratings for webers 2015/10/03 12:19:08 (permalink)
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    Holley 465 four-barrel carb has equivalent flow to a 658 two-barrel Holley, which does sound rather big!  David Vizard tested a stock 32/36 Weber at 288 cfm (in Holley 2 barrel speak), so a 350 isn't that much bigger than stock, although almost all have synchronous throttle opening, which is not ideal on a small engine like a Pinto.

    WTB: Recaro seat - any condition considered
     
     
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    NQRS
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    Re: CFM ratings for webers 2015/10/03 23:18:27 (permalink)
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    Some interesting facts there, gents. Have found the engine to be smoother at lower revs, and with cam, headwork/ porting and higher compression certainly no lag when acceleration is called on. Might not do so well on standard engine. Used holley's extensively in my younger days so far more at ease with jetting/ power valve setup. This is a later design one and has been modded for performance.
    Cheers,
    Len
    #5
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