Best Holley carb for 347 stroker combo?

[fasttback]

Just to throw in my 2 cents:

I ran both a Holley 650 HP and Mighty Demon 750 on my stroker (352). My motor is a similar build but has a little more cam than yours and it seems to favor the 750 through most of the rpm range. I did notice a little more throttle response at low rpms with the 650, but the car moves with either carb. Have fun with the new motor.

 

[machnone]

same problem different set up

my 72 has a 351c w/ unknown cam and unknown bore&stroke w/ 4v quench heads and single plane manifold .the old carb was a 750 dp that leaked as much fuel as it pumped .
so i went looking for a new carb and found much to my delight a chuck nuytten preped dp of unknown cfm. i suspected a 800 or 850. well after i bolted it up and ran it a few times i was concered that it might be to much carb. turns out it apparently flows around 1050 obviously a bit more than i was expecting . i am running a top loader w/373: or 390: i dont recall.
so my ??? is what can i do to lower the cfm short of buying a new carb
this set up craps out under full throttle for a full second or two
im sure ive left out some important info .

 

[D.Hearne]

my 72 has a 351c w/ unknown cam and unknown bore&stroke w/ 4v quench heads and single plane manifold .the old carb was a 750 dp that leaked as much fuel as it pumped .
so i went looking for a new carb and found much to my delight a chuck nuytten preped dp of unknown cfm. i suspected a 800 or 850. well after i bolted it up and ran it a few times i was concered that it might be to much carb. turns out it apparently flows around 1050 obviously a bit more than i was expecting . i am running a top loader w/373: or 390: i dont recall.
so my ??? is what can i do to lower the cfm short of buying a new carb
this set up craps out under full throttle for a full second or two
im sure ive left out some important info .

If you can wait a month or so, I'll have the 3310 750 carb off my 89 Ranger's 5.0 up for sale. Cheap. Just scored a 570 SA for it on ebay last weekend. Youy could then sell the carb you've got now to someone who could use it better.

 

[D.Hearne]

There is a little more differences between the 4150 and 3310 than some people understand. The DPs have different boosters, usually have 4 corner idle, progressive secondary throttle linkage, and of course, another accel pump assembly. They have much snappier throttle response due to a stronger signal and are calibrated with richer idle and air bleed circuits. They cost nearly twice as much and suck down fuel at alarming rates. But they can wake up an engine. I have owned the 600 and 750 vac secondary carbs and several DPs- the DPs are just a better carb for a serious build.
In fact, I just ordered the 750 HP main body for my 750 DP. My 530 HP 408 can probably use a few more CFM than the 750, so I thought for $125 I'd try it before I maybe get a 800 or 850. BTW, carb prices are getting ridiculous!

I too, noticed a lot wrong here like Dave did. So I won't repeat what he said. DP's do not cost twice as much as a vacuum sec. Holley. And carb prices haven't moved much at all in a few years, unless you're shopping for tuner carbs. Good little used Holleys can be had for less than $200. I see em all the time. Many are from guys who don't understand em, and give up on them. I pick em up for $125-150 and invest a kit in them and use em. There are so many out there, it just makes no sense to me to buy new.

 

[machnone]

sounds like a plan . but im a huge fan of not messin w/ stuff that im no good at. like rebuilding carbs. so i may just find a rebuilt or a new one but if yours is workin good and the price is right we can deal
im sure that my carb works fine its just to much.

 

[D.Hearne]

OK, cool, I'll let you know when. This 3310 750 works great, it's just a tad big for my engine too. I bought it a year or so ago for a trade off deal to get the 600 carb back my kid sold to a friend, but he changed his mind after I bought and rebuilt it. It was almost new when I bought it. Been on the Ranger for a year or so now and never missed a beat.

 

[machnone]

i have a new 750 dp on my 70 xl (390pi) and on the 69 440 superbee .but i dont want to canabalize one project for another( 2 steps foward 1 step back )so ill just move onward and upward,or at least sideways. but if any carb guru out there knows how i can desquirt my firehose of a carb please im all ears .
i mean its almost new and im sure it cost the origonal buyer absolutly bucketts of cash .so i hate to waste it.

 

[ratio411]

my 72 has a 351c w/ unknown cam and unknown bore&stroke w/ 4v quench heads and single plane manifold .the old carb was a 750 dp that leaked as much fuel as it pumped .
so i went looking for a new carb and found much to my delight a chuck nuytten preped dp of unknown cfm. i suspected a 800 or 850. well after i bolted it up and ran it a few times i was concered that it might be to much carb. turns out it apparently flows around 1050 obviously a bit more than i was expecting . i am running a top loader w/373: or 390: i dont recall.
so my ??? is what can i do to lower the cfm short of buying a new carb
this set up craps out under full throttle for a full second or two
im sure ive left out some important info .

A misconception about having too much carb is that the engine will not run well at all, no matter what you do.
Not true.
You can make a 1050 run beautifully on your car.
What makes it overcarbed is the power you leave on the table in the lower RPM range AND the fact that it is usually very hard to tune properly.
I submit that if your 1050 is 'crapping out', especially under WOT, where it's size should shine, then it is just out of tune.

If you do not know about tuning carbs, you really NEED to pick up some books on how to do it. Especially books geared specifically the brand carb that you have.
Some faithfull reading will teach you much.
Suddenly the lightbulb will turn on and you will think "that's why it did that!".
It seems complicated, but it not a black art.

With some more study, you will soon realize that all the folks that bad mouth Holleys (or Holley based carbs), just didn't know what they were doing!
Rather than admit they didn't understand how it works, they will put it down.
Save face and use a much lesser carb because it doesn't need tuning.

 

[gsxrken]

Why are you trying to confuse the guy?
There is so much wrong with your statement, I don't know where to start!
4150 is a carb family designation, as is 4160.
It has nothing to do with the specific carb part number 3310 or how many accel pumps it has.
DPs do not have 4 corner idle as a group.
DPs do not have annular boosters as a group. (You didn't say 'annular' specifically, but they are pretty much the only choice of "different" boosters.)
AND under a different part number, a 3310 can be a 4150 with only the addition of a metering block in the rear. As a 3310, it is a 4160... as a Street Avenger, it is a 4150, but still only has one accel pump.
A single pump, vac secondary, has the exact same accel circuit, therefore they can be just as "snappy" as a DP... Sometimes snappier because you are not force feeding a second accel pump circuit.
AND they all have "progressive" throttle linkage as the only other choice is 1:1 throttle linkage. Just that the DP is progressive mechanically, the VS is progressive at the will of the engine. Not to mention that you linked progressive linkage only to the 4150, when a VS can be 4150. You contradicted yourself.
Dave

Dave, good discussion, you can debate a post without me thinking you are a "dick".
Let me correct the record for clarity's sake and state that the double pumper 750 is a 4779, (in the 4150 family) and the vacuum secondary 750 is a 3310 (in the 4160 family). My use of 4150 to mean DP is not comprehensive of the Avengers, which you pointed out. I might as well add that the closest avenger is a 770CFM, part 81770.
If you purchase a DP 750 today, it will have 4 corner idle screws.
Some DPs have annular boosters, most have the downleg. In talking to the tech line just last week, the 750 HP DPs have an "improved" booster, whatever that means.
My use of progressive linkage was meant as you took it, meaning they open in direct relationship to accelerator movement, rather than wait for engine load to open the secondaries. But give me an F on that sentence.
Lastly, in terms of calibration, I believe the DPs, vacuum secondaries, and Avenger series (if we can distinguish them as a 3rd type for minute) all have their own out of the box fuel curves via application-targeted sized air bleeds, idle passages etc. I recall literature that discussed how the electric choke models were "leaner" for emissions, whereas the manual choked ones were "performance-oriented". But if you have any tech on this, I really would be interested in learning something here.

After thinking about it, I have lived with Holleys (of all sorts) on my cars continuously since 1983, when I put a "Summit combo" edelbrock intake, holley 600 vacuum secondary, and 14" air cleaner on my 65 289 coupe... for the grand total of $199. So prices have crept up since then(!), but even at today's prices, a 3310C is $272, whereas a 4779 is $435. While not double, $163 more (on a base of $272) is a LOT more in my book.

I stand by my experience that the DPs always hit harder than their vacuum cousins. I've sorted many carbs at the track and on engine dynos, and rebuilt more than my share. To quote the Holley website itself, "The mechanical secondary carburetor is best on a lighter car with radical camshaft and a lower gear and manual transmission or on a car that is going to be used for racing purposes." That describes the cars I build better.

As always, I only hope to add rather than take away from the board's knowledge, and learn something now and then too.