best carb for a 440 auto w a mild cam

[dixiedog]

looking for the best carb for a 1970 challenger auto trans, 323 suregrip rearend, 440 (1977) with a Holly Street Dominator intake, mild lunatti cam and lifters.  I am wanting one with mechanical secondarys.  I know less than nothing about carbs.  My brother-inlaw insists I use one with mechanical secondarys.  Thanks Danny

[MEK-Dangerfield]

I have a Proform 850CFM on mine, and I love it. You have a choice of going with a choke or without. If you go with a choke, definitely choose and electric choke over the old manual cable type.

[the_engineers]

I'd actually go with the classic 0-3310 Holley 750 cfm.  The 3.23 gears tells me you're not racing and a 440 should give you good enough vacuum signal to avoid any bogs from being out of tune.

Why does your BIL want you to get a double-pumper?

[4 speed fish]

I have the holley street advenger 870.Great carb for the price.Car runs strong.

[ireland383]

I agree with a Holley 3310. You really don't want mech. secondaries with an auto and a car over 3000lbs.

[challngd73]

Im no expert, but every thread I read that suggests a 750 on even a stock 440 has Chryco shaking his head.   I would say an 850 proform would suite you perfectly.  Just like MEK suggested.

[Road_Runner]

If you're not concerned about absolute horsepower and would rather have crisp throttle response in normal around town driving I'd be careful not to overcarb your motor.  Although an 850 would probably work, the 750 would probably do better especially since you're running a normal highway friendly rear gear.  So even at 65-70 mph you're not going to be turning a bunch of rpm.  Bigger is not always better when it comes to carbs.  The best throttle response I've ever gotten on my built 383 Roadrunner was with a small 650 Carter on a dual plane Edelbrock manifold.  I ultimately installed a six pack setup which gave me a lot more horsepower in the mid & upper rpm range, but didn't really care for low rpms like you'll be seeing with your setup.  Just my .02. 

Later, Jim

[Chryco Psycho]

Chrysler factory installed an 850 vacuum secondary Thermoquad carb on a 340 in 72 with low compression you want to install a 750 on a 440 Why??

[Chryco Psycho]

when I was 18 I installed a  950 vacuum secondary on a stock 440 in an R/T Challenger with 3.23 gears , it worked great & had far better throttle response than the factory 625 carb

[challngd73]

I dont think there is another thing that can set Chryco off like under carb'n a 440

[dixiedog]

Thanks guys, yeah Chryco is addiment about an 850 or bigger.  He has helped me a ton in the last year.  After investing over 20k in this car money is running out.  I checked out the proform 850,   Will see what I can come up with.  Thanks again, Danny

[Road_Runner]

Chrysler factory installed an 850 vacuum secondary Thermoquad carb on a 340 in 72 with low compression you want to install a 750 on a 440 Why??

True, but the TQ had smallish primaries and larger secondaries so you were running on just the small primaries most of the time.  With the square bore carbs you're obviously running on 'half' the carb until you kick it.  I'm not questioning your advice, I'm just saying a 750 double pumper would be more than adequate on a mild 440 if crisp low rpm throttle response is important.  On my 383 I ran a carter 650 until I rebuilt the motor adding a lot of cam & compression and then either ran a sixpack or 780 Holley on an original Torker.  But I'll bow to your greater experience with 440s specifically if you say they need at least an 850 to run well.

Later, Jim

[challngd73]

Its really in the eye of the beholder...If a little better fuel economy is what you want out of your 440, and really arent conscerned with all out performance, then a 750 will still run good.  But I didnt get a 440 for fuel economy:)

[Chryco Psycho]

well the 440 I used the 950 on was stock as in stock intake & iron exhaust manifolds , point ign , stock air cleaner etc.
 
I am not saying a 750 will not work , you could put a 500 CFM 2 bbl on a 440 & have good throttle response but as a few people who have followed my advice will tell you even though the engine runs great you have no clue how much you are giving up / missing out on with a small carb .

 Personally I love mechanical secondary carbs , sometimes they will bog no matter how well you tune them so you have to learn to drive them a little instead of flattening the throttle at 1200 RPM . you just have to 1/2 open the throttle until maybe 2000 rpm or so to go wide open .

 I built & tuned a 512 CI with a Proform 950 on top & still managed to get 17.6 MPG on the highway with it so a smaller carb may not even beat the fuel mileage either 1

 If budget is an issue grab a 3310 or an Avenger for $100 or so for now .... the point is the title asked what is the "best carb "

[challngd73]

The Proform is truly a high quality Carb, I will be installing mine soon.