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CARB CFM

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PROSTOCKTOM View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PROSTOCKTOM Quote  Post ReplyReply Direct Link To This Post Posted: Sep/18/2018 at 7:52pm
You could always buy a pair of 390 cfm Holley's

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: Sep/19/2018 at 4:55am
IMO two 390 Holleys would be way too small. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: Sep/20/2018 at 6:49pm
Getting creative three Carter AFB need 18.75" if you get real creative
and scrunch them together. This places the throttle plates in a reasonable
location on a elongated plenum with a 4.75 cl or motor like a AMC or a BB Buick
and others with Cadillac being 5" for 425 - 500.

The water spigot would have to be re-located and there could be no wiper motor...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pwrslide Quote  Post ReplyReply Direct Link To This Post Posted: Sep/21/2018 at 2:52pm
Running 2 Edelbrock 1804 500 AVS on a UR18 on the street. Great right out of the box. Instant throttle response with a Schneider 279 mechanical cam in a built 401





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Post Options Post Options   Thanks (0) Thanks(0)   Quote PHAT69AMX Quote  Post ReplyReply Direct Link To This Post Posted: May/02/2019 at 5:18pm
Have learned a couple things...
The Hurst S/S AMX 4584 ~585 CFM Carbs, and the current List 9776 450cfm Tunnel Ram carbs,
have very small secondary Main Air Bleeds that make the Boosters start-up very quickly
to make up for the absence of the secondary accelerator pump...

BUT... the 9776 450's are "too small" BECAUSE they have smaller 4x 1-1/2" Diameter Butterflies !
AND... the 4224 660's are "too big" BECAUSE the have larger 4x 1-11/16 Diameter Butterflies !
SO... the 4776 600 DP's are "just right" BECAUSE they have 4x 1-9/16" Diameter Butterflies !
Just like original S/S AMX 4584 SP Carbs, AND the '68 sbc 302 Xram List 4210 SP and later 4295 DP
which the S/S AMX List 4584 Carbs are derived from / made out of.
  
Brian Higgins S&K Speed ran the 4584's on S/S #19 made me aware of the 4584 tiny Secondary Air Bleeds.
And research done sure seems to imply the Hurst AMX 4584 carbs are "re-numbered, re-applied"
1968 Chevy 302 Camaro Trans Am CrossRam 1st Design Holley List 4210 carbs...
which were quickly superseded by GM within a few months by 2nd Design List 4295 Double Pumpers
which just happens to be the very 1st Holley Double Pumper Carburetor, at least it appears to be so far...



Edited by PHAT69AMX - Dec/14/2019 at 9:17pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 6768rogues Quote  Post ReplyReply Direct Link To This Post Posted: May/02/2019 at 7:06pm
For racing-Holley. They are great for wide open throttle. Kind of like a big toilet flushing gas into your engine.
For the street-Edelbrock. They have great mid ranges and tip in response. Very drivable throughout the ranges and good gas mileage.
Content intended for mature audiences. If you experience nausea or diarrhea, stop reading and seek medical attention.

Located usually near Rochester, NY and sometimes central FL.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: May/02/2019 at 7:24pm
Yep.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote one bad rambler Quote  Post ReplyReply Direct Link To This Post Posted: May/02/2019 at 7:34pm
I run a pair of 600DP...They required some tuning but the set up is night and day to the Torker and 750 i ran before it....In this video i hit 1st and 2nd with the slicks on....            https://www.youtube.com/watch?v=RNjGAL0qpUs
68 AMX 390 4 Speed,68 American,64 American 2 Door Wagon Altered Wheelbase,78 Concord Build 360,727,8.8
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: May/03/2019 at 12:10pm
As stated in a previous thread, there are many calculations for carburetor CFM to displacement, RPM range, exhaust flow, intake flow ... But they don't seem to work for a dual 4 barrel.
Buddy changed from 2x750 to 2x1050 Demons on a Dart 502 motor and it has never run better.
The math say's that 2100 CMF of carburetor should never run right, but tell that to the engine, as it has a very different opinion.
Would not be afraid of going bigger rather then smaller on this type of setup.
My changed opinion. 
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