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Discussion Starter · #1 ·
As my signature notes,I have a crate 350/330 motor in my 66.Im considering changing the cam in it this winter to the Comp extreme 268h.So my ?? is will the 600cfm Edel.carb be enough or would I gain much by going to a 750cfm carb...? What do you'all think???

Rick

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66 300 Deluxe 350/330hp
71 350 malibu (project car)
72 Elcam 402SS
78 Malibu Classic (daily driver)
 

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How To Calculate CFM:
Engine size (CID) x maximum RPM / 3456 = CFM
CFM @ 100% volumetric efficiency

Use that, it'll tell you exactly what CFM carb you need.

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kenny

85 El Camino 355ci
350 turbo - 4.11's
best run so far 12.92
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Yes, that formula will get you to a starting point.

Remember that four barrel carbs are rated with a vacuum of 1.5". Since you don't want a 1.5" vacuum in your intake manifold at WFO, you may need a larger carb, depending on your V.E. and driving style.
 

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Well, for what its worth, my old Bomber currently runs a 600 Carter on its 406. Yes, in my case it does choke it down a bit - the 1/4 mile dropped from 108 mph down to 106 mph, but the e.t. did not suffer any.

Now I know that my combo is not really dialed in as well as it could be. But for all of you guys out there with mild performance 350's who are worried about whether you need a 750 I just wanted to show an example of an even larger smallblock that runs fine with "only" a 600 carb.

The longer you read Team Chevelle and other like minded sites, you will begin to realize the performance equation revolves more around the total car/drivetrain combination than any one given component.

The question that needs to be more directly addressed in the pursuit of acceleration is: where is there a bottleneck in the combination? If indeed it can be proven that for your car's weight, gearing, rpm range, etc that it is starved for air - then, and only then, should you look into a larger carb. But even before you bolt on a larger carb you need to determine if the manifold and cylinder heads and exhaust system are up to the task (can they support the extra airflow capacity of a larger carb).

I'm guessing that you are doing more general cruising with this '66, so I would strongly suggest the 600 carb over the 750. And the Edelbrock 600 is a near copy of the Carter carb, so you are assured of an easy to tune and good road mannered carb.

Best of luck, Thomas

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"Bomber" '67 El Camino, Beater comes back to life.
Was 350/TH350 14.90 @ 93mph, 360,000+ miles on car
Now 406 roller, 340rwhp, more hp coming, 3.08 gears
Street radials, left in drive, 13.20 [email protected] mph
8/1/01 added Plum Mist '67 to collection
*New* 468 on its way - going Big Block!
 

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I have a 600 edelbrock on my 350, i replaced a quadrajet. It runs better down low and in the mid range , about the same on top.

What are you running now?
 

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This weekend i put my new 750 cfm dual feeder on my 350 cbi. It needs to be tuned, but already performs ok. (I'll removed the 600 cfm, he didn't run good)
 

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Discussion Starter · #7 ·
I have the Edel.600 on it now.
I was wondering if it would be worth the extra $$$ for the 750cfm...The motor has the "vortec heads",Edel.performer manifold,headers,th350,and 3.36 gears..

Im also planning on changing the th350 to a 200r4 or 700r4 also this winter..
Rick

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66 300 Deluxe 350/330hp
71 350 malibu (project car)
72 Elcam 402SS
78 Malibu Classic (daily driver)
 

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66 El Camino 57 Chevy pickup 2004 Tahoe
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I've worked on several of these, pulled the 750 which was giving sluggish throttle response on the low end up into the mid-range, used Holley and Edelbrock 600's and Q-jet. They all ran much better overall, no body has complained about loss of power on top and all report much better seat of the pants feel and driveability.

FWIW, YMMV, all that...

Tom
 
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