Correct carburettor sizing for a stock-ish 440

theseoldcars · Post by **theseoldcars** » Sun Nov 01, 15 6:19 pm

Evenin' all. The 440 in my Charger currently has a 600cfm Holley four-barrel carburettor atop it. It's a vacuum secondary and, credit where it's due, it seems to work quite well.

It's getting on a bit, though, and I'm wary that it's a little too small for the 440. Mine's no high-comp monster ('72 motor, headers, Edelbrock CH4B intake, uprated ignition) but the consensus seems to be that I'd be better off with a 750cfm vacuum secondary (got a 727 behind the motor).

What's your preferred sizing and brand? I like the Holley on this, wasn't too fussed by the Edelbrock I had on my Firebird previously... but at least it worked, unlike the Demon that it came with, haha. Swings and roundabouts.

Do like the look of the Quick Fuel Technologies 750cfm that Summit offers. Only about £330 landed and cleared through customs.

I do have an 850cfm Thermo-Quad in need of a rebuild, too. Lots of people have nothing but good feedback about the way they perform but I think this one would probably need a bit too much time and money sinking into it.

Pete · Post by **Pete** » Sun Nov 01, 15 7:10 pm

Opinions will vary wildly.

For my part I would always go for a Holley or Holley derivative.
They are much easier to fine tune with limited tools.

750 Vac sec or thereabouts will be fine.
Some of the Street Avenger series are good.

Blue · Post by **Blue** » Sun Nov 01, 15 7:22 pm

750 Holley, personally I'd use a double pumper 'cos I'm not keen on vac sec carbs.

Pete · Post by **Pete** » Sun Nov 01, 15 8:04 pm

I too prefer DP carbs, but I assumed it was a Dual Plan manifold for road use so a DP may be a bit OTT.

theseoldcars · Post by **theseoldcars** » Sun Nov 01, 15 8:55 pm

Sounds good. Correlates with what I've read on countless forums, too, barring one user who's adamant that anything under 850cfm is not enough for a 440, haha. Perhaps at 6000rpm, but mine's not going anywhere near that!

Think I'll start shopping for a decent vacuum secondary 750cfm Holley-style carb, then. At least I'll have a great starting point.

Cannonball · Post by **Cannonball** » Sun Nov 01, 15 10:10 pm

theseoldcars wrote:Sounds good. Correlates with what I've read on countless forums, too, barring one user who's adamant that anything under 850cfm is not enough for a 440, haha. Perhaps at 6000rpm, but mine's not going anywhere near that!

Think I'll start shopping for a decent vacuum secondary 750cfm Holley-style carb, then. At least I'll have a great starting point.

I built a bitsa 440 for a mate off mine all used parts nothing special cept 6 pack pistons out of another engine i broke fitted in his 70 cuda full weight nothing removed or lightened 3,23 gears 600 vac sec holley
12,9,s 104 mph, dont knock a little vac sec, for good all round use,

Adrian Worman · Post by **Adrian Worman** » Sun Nov 01, 15 11:11 pm

I'm with Dunc, if you're not goin to lean on it & want a perfect low rpm signal for impeccable road manners stick with a 600/650cfm

All carbs work and can be tuned to work, but a carb is a constant compromise by its nature & you need to decide exactly what you want from your car.

db · Post by db » Mon Nov 02, 15 9:45 am

My 360 is quite a lively one so on advice I've been trialling 750 and an 850 dp carbs. The 750 gives it great road manners and plenty of go, the 850 is hard work. Exciting but you have to drive aggressively ALL the time, gets a bit tiring!
750dp is a great carb when set up right!

Steve · Post by **Steve** » Sat Nov 07, 15 4:02 pm

My 383 Hipo in my Polara runs great on a 600cfm 1406 Edelbrock, and my the 440 in my New Yorker runs fine on its 670cfm Holley....from what I have read, a lot of folks think they need a much bigger carb than they actually do, dependent on their application. Im after good street manners and the od traffic light blip to annoy the hot hatches in my Polara so 600cfm is fine for me.

There are plenty of online carb calculators ... you will be surprised at what size most of them recommend, smaller than you think!

Pete · Post by **Pete** » Sat Nov 07, 15 4:08 pm

You mean your 383 Hipo in your "C" Body Hippo

Steve · Post by **Steve** » Sat Nov 07, 15 5:11 pm

...............

Pete · Post by **Pete** » Sat Nov 07, 15 5:16 pm

I think the truth is that a softly tuned Big Block will run on a variety of Carb sizes.

I can remember Roger saying that when they dynoed his 500 stroker it actually made more power on a 750 than an 850.