Re: venturi size of 850 and 950 holley?
[Re: B1MAXX]
#1333640
11/11/12 12:05 PM
11/11/12 12:05 PM
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Joined: Jun 2008
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usa
lewtot184
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Quote:
I'm just going off memory but I think that the Holley 950's are 1.38 and their 850's are 1.56.  I never "got" the 950 rating based on that.
you're correct on size. the 950cfm rating is bogus.
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Re: venturi size of 850 and 950 holley?
[Re: lewtot184]
#1333641
11/11/12 12:29 PM
11/11/12 12:29 PM
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Joined: Oct 2003
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NE Oklahoma
Von
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[quoteyou're correct on size. the 950cfm rating is bogus.
Or is the 850cfm rating bogus? Or is the 1000 cfm rating bogus on the HP carbs which have the same size venturis and throttle plates as the 4781 850s?? 
Or should all CFM ratings be taken with a grain of salt?
The 950 PF main body venturis are smaller than the Holley 950 main body.
72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72.
Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.
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Re: venturi size of 850 and 950 holley?
[Re: Von]
#1333643
11/11/12 01:24 PM
11/11/12 01:24 PM
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lewtot184
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Quote:
[quoteyou're correct on size. the 950cfm rating is bogus.
Or is the 850cfm rating bogus? Or is the 1000 cfm rating bogus on the HP carbs which have the same size venturis and throttle plates as the 4781 850s??
Or should all CFM ratings be taken with a grain of salt?
The 950 PF main body venturis are smaller than the Holley 950 main body.
i believe all the HP ratings are inflated. the older vacuum secondary and double pumpers are closer to their ratings. i don't pay much attention to cfm ratings. it's just a marketing ploy that the buying public has taken hook, line, & sinker. it's easier for most people to take the manufacturer's rating as gospel than to dig into the statistics of the product and make an informed decision.
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Re: venturi size of 850 and 950 holley?
[Re: mopar dave]
#1333647
11/11/12 06:27 PM
11/11/12 06:27 PM
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Joined: Jan 2003
Posts: 31,030
Oregon
AndyF
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Quote:
anyone know the venturi sizes for 850 and 950? just curious here as i have what bigs performance calls a 950 stage 5+,but the main body is stamped 850 and has 1.400 venturi's.
A 1.40 is a fairly small venturi carb. Works well with smaller engines, or lower engine speeds. Nothing wrong with a 1.400 carb, you just need to match it up to the correct engine. Holley now has a 1.590 venturi in the new aluminum carbs. That carb really makes the power on a big engine.
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Re: venturi size of 850 and 950 holley?
[Re: emarine01]
#1333649
11/11/12 07:04 PM
11/11/12 07:04 PM
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Joined: Feb 2005
Posts: 4,313
Prospect, PA
BSB67
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It would be nice to see actual flow data using a standardized method conducted at several different differential pressures, say .5 to 2.0 "hg.
Venturi size is not necessarly the defining element for air flow. There are several aspects that will effect the flow. Slight changes in shape and contours can have a large impact on air flow.
Another item of note is that on my 4781, the boosters are different than on my 950. They are thicker and look like they would be more restrictive to flow.
With all that, it is hard to believe that the 950 (1.375" venturi) flows more air than the 4781. However, on my car, the 950 is 1 mph faster, and .2 sec quicker.
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Re: venturi size of 850 and 950 holley?
[Re: BSB67]
#1333652
11/11/12 07:42 PM
11/11/12 07:42 PM
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lewtot184
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Quote:
My low et in cool air was 77/84 in my 950.
for me, knowing your engine and car, the smaller carb may have created a torque advantage thru the power band. i also thought the smaller carb had some a/f issues. did that get resolved?
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Re: venturi size of 850 and 950 holley?
[Re: mopar dave]
#1333654
11/11/12 08:36 PM
11/11/12 08:36 PM
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robin hood country
deaks
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I thought the smaller venturi on the 950, made for a better shift recovery.
Andy, what exactly do you mean by a larger engine.
500 and up ?
Mick
69 Dart GTS 440 mopar .590 cam, Edelbrock heads, 3200#
best et 6.45, 106.78, 10.14, 132.88 mph, 1.47 60ft
best 60ft 1.36
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Re: venturi size of 850 and 950 holley?
[Re: lewtot184]
#1333655
11/11/12 11:34 PM
11/11/12 11:34 PM
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Joined: Feb 2005
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Prospect, PA
BSB67
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Quote:
Quote:
My low et in cool air was 77/84 in my 950.
for me, knowing your engine and car, the smaller carb may have created a torque advantage thru the power band. i also thought the smaller carb had some a/f issues. did that get resolved?
Still rich in transition.
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