i got a holley 650 double pump carb that i had on my 340 before. now im soon gonna be ready to put my 416 stroker in. is my carb gonna be big enough to supply it?

thanks in advance

According to Holley.Com, YES. 650 CFM should be fine for your 416 CID (depending on maximum RPM.) A 700 or 750 CFM might work well too.

View the Holley Chart (link below) and remember, you never get 100% efficiency from a naturally aspirated engine (more like 85% to as-much-as 95%, but that is closer to a Pro Stock engine.)

On the lower end (6,000 RPM, 85% V-Efficiency) a 637 CFM carb is enough.

At maximum 8,000 RPM, 85% VE, an 800 CFM carb would be a better choice.

The 650 CFM is good to 6,000+ RPM though you should make some upgrades to that carb (correct Power-Valve, jetting, accelerator-pump, squirters, etc.

Generally speaking, the smaller the throttle bores,the better the throttle response. Also, a mistake many people make is over-carburetion.

Here is the Advice directly from the Manufacturer (Holley) on selecting the Right Size Carburetor:

Selecting the Right Size Carburetor, Holley.

Well you didn't say what heads and cam you were running. Or whether it street or strip. My W2 headed 416 with a 272@050 612 lift cam. Loves my 950HP. IMO a 650 will not allow that motor to run to it's full potential. Jim

That thing will be a PIG with a 650 Holley. I am pretty sure on a build like this VE goes up to around 120 percent not down. A 650 may run it but I would be money that a 750-950 Holley would be more in the ball park of what it wants. Even if it had a stock cam and heads I would't go any smaller then a 750.

Yea holley is way on the conservative side for a reason. people are morons and this way they don't get people back saying it won't idle that carb you suggested is too big. for street strip I like max shift RPM and 120% as we know it (for the sake of a mental visual) say only takes 200 cfm to go 70 mph if you open the carb to where it will flow 200 you start out and the closer you get to 70 the slower the car picks up speed. Now if you mash it it gets up to 70 toot sweet but was it not to big a carb to go 70 yes but ut has to have more available air than need to accelerate.
so 416 X 6500 / 3456 = 782 X 1.20 = 938???

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Well you didn't say what heads and cam you were running. Or whether it street or strip. My W2 headed 416 with a 272@050 612 lift cam. Loves my 950HP. IMO a 650 will not allow that motor to run to it's full potential.

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Make that "two" satisfied 950 Holley users, we just dyno'd my friends 422 340 stroker, ported W2 heads, milder cam than above, still liked the 950 over a 750 DP, and an 800 AVS ("liked" = about 30 more HP than either of the other carbs). We never ran a Thermoquad but I'd say a nicely tuned TQ would hold it's own against any of them in terms of overall performance.

Wasn't the stock carb for a 340 in 68 a 650 then in 72 was it not a 850 Thermo Bog??
Guess mopar did not know what they were doing!!
650 + 22% for the 22% bigger engine 800??? then more rpms with a racy motor???

Dodgem,

Not sure how much of your reply was serious or not but for the record the 71 340 cars (850 TQ) were potentially the fastest 340 cars ever produced, and allot of it had to do with the carb. The only people who call Thermoquads "Thermo Bogs" are those that just don't know how to tune one. When right they can be monster carbs and almost infinately adjustable.

It's just the name I had one working good on a cammed, headered 318 stock 360 heads and 7.5 to 1 compression truck no bog and dam would it pull especially compared to a 600 eddy and a 600 holly. now I ran my best times with the truck with the 750 vac of my 440 but never had the thermo yet so only seat of the pants comparison. (and the thermo relly pulled past 4000 maybe better than the 750 Vac??) course when I sold the truck it went with the 600 holley and the thermo bog went on my 1980 360 truck just replaced the needed to be rebuilt thermo bog that was on it and many happy motoring years with it.

I love them Thermo Quads. When you open them 2 bedroom size secondaries the sound and the kick in the butt fell. Shame they don't still make them. Back in the day them were the best carbs out there. To bad when Eddy bought Carter they scrapped the Thermo Quad.

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Shame they don't still make them. Back in the day them were the best carbs out there.

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It's no big deal that they aren't being made anymore, there are still plenty of good core originals out there (usually CHEAP) and most parts are still available. A thorough rebuild and you can have one that's as good or better than anything ever sold new.

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Not sure how much of your reply was serious or not but for the record the 71 340 cars (850 TQ) were potentially the fastest 340 cars ever produced

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Scott, The 340 TQ's were rated 800 cfm. They have smaller primaries than the 850's which were found on 400's and 440's (as well as a few 360's)

Hi Jimmy. I have an Aussie Charger with a stroker 440(496ci)& 4-speed. Have Stock Stealth Heads,1:7/8" Headers,Comp Cams 294S(248@050),Wiend Xcelerator Manifold,10:1 Comp: 193 psi cranking pressure running on 96 oct: pump gas. Have 2:75 gears out back & with myself & fuel on board it does 12:00@118+mph with an 850 Holley & with a 650 Holley does 12:3@116mph 1/4 mile.
Now,for the record,I run the 650 all the time on the street & it is just awesome. Pulls 6500 in 1st & 2nd,although it is starting to lay down about 5800rpm. What I'm getting at is the 650 Holley will run nice on your 340.
I use to have this same 650 on a warm 360 & it also performed flawlessly.
Oh! & I also went on a chassis dyno & the 850 made 419 horse-power at the wheels & the 650 made 406 horse-power. The only other factor was, the torque on the 850 climbed more straight up.
Cheers, Mike in New Zealand.

Yea Jeff, that's right, I was thinking of the 850 Competition versions when I typed that.

I have 340 mild cam headers eddys, and i tried all holleys, but a 650,700,750,830 comp series, and a ported 800, the throttle response was good with smaller carbs, but no good at the track, it ran the quickest with the ported 800 but it was a little to much the 750 works the best for all around, and i think it will work better after i do a port job to it.