850 CFM. carb on a 440.

[Highbanked Hauler]

   I always hear that some people use to large a carburetor on their engine. Is a 850 cfm.  double pumper  on a   moderately built 440 going to have the same problem ? I realize parts go into a motor as a package for a purpose.

[BSB67]

There is a lot of missing information to give a certain answer.  But generally, if it is indeed a well done moderately built 440 and it has a dual plane intake, it will work.

[Highbanked Hauler]

  The only thing I can say for certain is it has a TM7 manifold,  steel heads 1.6 Crane Roller  adjustable rockers and anymore would be speculation till I get a head off of it. It needs a "good" distributor and carb as I put a 600 Holley and an old points distributor just to get it running which it did but not well.

[c00nhunterjoe]

Still not enough information. If you over carb the engine, you can still jet it to run efficient, but it wont have good throttle response and will feel sluggish.

[myk]

I'm guessing that's why those online 'carb calculators recommend 'carbs that are much smaller than we would guess...

[John_Kunkel]

If you over carb the engine, you can still jet it to run efficient, but it wont have good throttle response and will feel sluggish.

That's the bottom line, overly large carbs kill drivability at all but WOT.

[Highbanked Hauler]

I'm guessing that's why those online 'carb calculators recommend 'carbs that are much smaller than we would guess...

   I got into "Holley.com" and they have a formula for carb.size. According to them all I need is a 750 cfm. for my particular situation and still have plenty left over.

     Formula is  cubic inch,   446 cu. in. for me,  times RPM. 5500 = 2453000 divided by  (3456) =  709.78009259259259    If I copied it right.  With a 4 spd. and 2:76 gears I don't think there is much danger of me hitting 5500 rpm..     Basically it will be a track laps car 6 or 8 times a year when I get the chance.

[A383Wing]

try this site...input yer numbers...meaning the numbers the car will see on an everyday basis

http://www.4secondsflat.com/Carb_CFM_Calculator.html

[Highbanked Hauler]

try this site...input yer numbers...meaning the numbers the car will see on an everyday basis

http://www.4secondsflat.com/Carb_CFM_Calculator.html

    The numbers came out exactly the same,  709.780 so a 750 cfm would be a bit much according to this.

[chargerbr549]

This is one of those questions you will get a lot of different opinions and experiences of different carb cfm's to use. I think generally 750 to 850 cfm range works pretty well on a street driven 440 depending on how it's built and what your driving style is, there are so many variables on what determines a good carb size, I think the carb calculators are a good reference but shouldn't be necessarily treated as gospel, also you have squarebore vs spreadbore as well as several different ways of opening the secondarys will determine what works for you. The 3310 750 Vac Secondary Holley is usually a pretty good all around carb that I am using on a fairly mild 500 in my Ramcharger, I have an 800 AVS thunder series carb on a relatively stock 440 in my pickup that works very well and also have an 850 proform double pumper on another engine that works well too.   Just my rambling and two cents worth.

[1974dodgecharger]

mopar engines like to be over carbed vs chevy or ford this has been proven over and over....those caluclators are for ford/chevy.

[A383Wing]

mopar engines like to be over carbed vs chevy or ford this has been proven over and over....those caluclators are for ford/chevy.

lets see your proof

[303 Mopar]

Keep in mind that the advertised cfm is not the true cfm.  I talked to Proform and my 750 cfm actually flows around 780 cfm.  Altitude also plays a big factor.

[1974dodgecharger]

mopar engines like to be over carbed vs chevy or ford this has been proven over and over....those caluclators are for ford/chevy.

lets see your proof

hot rod tested this many times over google helps.....they tell me my 383 needs only a 600cfm setup.  they overcarbed it to 1050 dominator saw no power gains over the 850DP.  I use a 750DP...im happy....

[morepower]

i ran an 850 demon on my 440 stock heads, cam, intake, headers 3.91 it ran good

[BLK 68 R/T]

I used to have a 70 Superbee with a 383 and a 4 speed. Motor was bone stock running a 625 edelbrock instead of the original holley. For fun I slapped on an 850 race demon that a buddy had for a weekend. I would swear it added 50hp to the engine, idled fine and ran like a raped ape. The 850 should be fine, if you look at the 71 340's, chrysler put that monster thermoquad on them and they ran really good in my opinion.