4BBL or Six Pack?

[69chargerboy]

I currently have a crappy Eddy 750 that's causing me headaches. The Eddy card isn't performing well, it feels like there is more power than it can handle.  I was wondering if there is a huge difference in performance and maintenance between lets say a Race Proform carb I'm looking at that will mate with my CH4B intake OR going with a six pack set up. Since I haven't had either, I was wondering what you guys think of what would be the best? I have a mildly built 440, performance cam (cant remember what it is..) .030 over, port/polished iron heads, HP manifolds, 2500-3000 stall, 2.5 TTI exhaust. Thanks. John

[AKcharger]

I really think its a question of $$$$ and how much its worth to you. a 6 pack will easily be 3-4 times the price of even the highest quality carb...but it does look cool under the hood.

When I was in high school 6 packs had a bad reputation as being finicky and hard to tune BUT that was after they were beat on for 10-13 years straight. I heard the new set ups are much better. Plus there are shops that will assemble, tune and test the whole set up before they ship

[cudaken]

 For Looks, 6 Pack hand down.

Why do you think the carb is to small, 750 CFM is a lot! 750 CFM should be good to 500 HP range. What sizes fuel line and fuel pump?

Cuda Ken

I am not a Eddy or Carter Fan, but anything that is not tuned right or lack of fuel supply will be a dog.

[Dmichels]

I had an Eddy carb on my motor for a few weeks I could not get it to run very good either. I have the ch4b as well. I think these carbs are tuned for the Chevy 350 crowd. They copied the old Carter afb and are a good carb. I guess I did not play abound with the jets, metering rods and springs enough.  I put on a Holley 800 DP and the car waked right up. I was more familiar with tunning Holley so it went well. Gave the Eddy to a friend for his Camaro and it runs good for him.
Dave

[Cooter]

6-Pack IMO, is Huge Money for a lot of trouble. 1350 CFM is a lot for even the biggest stroker motor. Anytime you get into Multiple carbs, you are asking for tuning nightmares.

Stick with the tried and true 700-750 Holley DP and play with it. I like to pick most of mine up a swap meets for pennies after someone cannot get it running right.

[heyoldguy]

I would think that the 750 Edelbrock isn't yet tuned for your engine.

I have used the 6-pack a time or two, run it for awhile, taken it off and sold it and went back to the 4-bbl. It looks cute but it's not really worth the hassle to me. Additionally, the 2-bbl carburetors are rated at a different vacuum than the 4-bbl carburetors. So if you do the conversion, you will find that the 6-pack rated at 1350 cfm will convert to about a 950 cfm 4-bbl.

If you aren't happy with the Edelbrock, that is reason enough to go to another style carburetor if you wish. Any of them will work well if you take the time to tune them properly.

[69chargerboy]

For Looks, 6 Pack hand down.

Why do you think the carb is to small, 750 CFM is a lot! 750 CFM should be good to 500 HP range. What sizes fuel line and fuel pump?

Cuda Ken

I am not a Eddy or Carter Fan, but anything that is not tuned right or lack of fuel supply will be a dog.

I have 3/8 fuel line and a mopar high performance mechanical fuel pump. It feels like it loses its breath on the top end...

[69chargerboy]

6-Pack IMO, is Huge Money for a lot of trouble. 1350 CFM is a lot for even the biggest stroker motor. Anytime you get into Multiple carbs, you are asking for tuning nightmares.

Stick with the tried and true 700-750 Holley DP and play with it. I like to pick most of mine up a swap meets for pennies after someone cannot get it running right.

Thanks for the advice Cooter, but I thought I have to stick with a carb with vacuum secondaries since I have an automatic. Would a mechanical carb like the Double pumper work for me?  Im Sorry, I don't mean to be a noob about this I just don't know a about carbs at all. 

[adauto]

6-Pack IMO, is Huge Money for a lot of trouble. 1350 CFM is a lot for even the biggest stroker motor. Anytime you get into Multiple carbs, you are asking for tuning nightmares.

Stick with the tried and true 700-750 Holley DP and play with it. I like to pick most of mine up a swap meets for pennies after someone cannot get it running right.

holley 750dP on my HEMI... 

[69wannabe]

You need a holley 750 on that 440!!! I have had good luck with the 600 eldebrock's but the 750 eldebrock's never worked for me at all. I ran a 4779 holley which is a 750 double pumper on my 440 and a friend of mine has a 750 vacumm secondary 750 holley on his 440 and it runs great too. Stay away from the street avenger carbs that holley has out there, had one of those on my 383 and it ran fine but I ran across a cheap 750 DP at a swap meet like cooter was saying and put a kit in it and stuck it on the 383 just to see how it ran and it woke that little engine up big time!!!! I had a 670 street avenger on my 383 to begin with but once I tried the 750 DP out on it I never went back to the other carb. The proform 750 would be a good carb too!!

[Scaregrabber]

A 750 holley double pumper or vacuum will work great with a 440 automatic. The vacuum will probably give better fuel mileage depending on your driving habits. Better than a 750 Edelbrock AFB for sure. I do like the 800 AVS though.

Sheldon

[Tom Q]

oh boy more six pak whining....a properly tuned six pak will always out run the 4bbl.

There is plenty of good information on how to make the 6 pak work properly.
PM me and  i will send you the tuning guide or go look for it on moparts.

You do not need 3/8 fuel lines to support most six pak engines.

I ran a 400 rear wheel hp six pak engine on 5/16 fuel lines with no problems on the road course [of all places!] with a mechanical fuel pump.  130 mph on the straightaway... 3.4 miles per lap...

[Cooter]

Thanks for the advice Cooter, but I thought I have to stick with a carb with vacuum secondaries since I have an automatic. Would a mechanical carb like the Double pumper work for me?  Im Sorry, I don't mean to be a noob about this I just don't know a about carbs at all. 

Yes, it will work way better than multiple carbs. Keep it simple. A 4BBL properly tuned will always outrun a 6pack because 9 times out of 10, the 6 pack is suffering from tuning issues like 90% of them on the road. Do you research at local car shows. Ask around about 6 packs. Many will tell you the same things we've told you here. After all, we could be condescending and recommend a 6 pack for your ride, but most of us here wanna actually help you.

[b5blue]

  My six pack has been reliable for 18 years. (and it's 44 years old.) Paired with the correct carter fuel pump for high volume without high pressure it has run just fine. To boot when your driving easy you get much better mileage I've found. I'm not saying "get one" just saying their not troublesome.   

[c00nhunterjoe]

Yeah, 6 packs are junk..... tell that to my buddy's road runner....

[Back N Black]

Hard to choose which carb with so many different opinions. Anyhow, i have a Holley 770 Avenger, vacuum secondaries. It works great, I'm running a 500 hp 440 and two pumps in the morning and it fires right up and when engine is warm turn the key it fires. It pulls hard with no issues at all.

[heyoldguy]

I don't have a favorite carburetor, I run everything from the Edelbrocks to Demons to custom built Holley Dominators. You can keep changing carburetors at $350-$750 a pop until you get one that works for you. BUT, do you have the tuning book that Edelbrock provides with every 750 carburetor it sells? Have you followed the instructions in it? Every engine I have ever seen eventually runs out of breath on the top end. My 500 wedge runs out around 8000 rpm. What is the top end you are struggling with, what rpm? What gears and tires?

If you don't know what cam you are running, is it the cam and the way it is timed? How are your valve springs?

What timing are you running in the distributor? 

Shiney ported and polished heads means nothing unless you have flow numbers to go with them. I have seen "ported and polished" heads that flow no better than stock heads.

Let's get real guys, it's a guess as to what carburetor MIGHT work on this engine combination if the owner has not tuned what he has already got.

[6spd68]

Agree with the above statement...  But if I had to chose, Holley 750 VS all day.  Have had one on my T-bird's 347 for a few years, always runs great and has never let me down.

[Dino]

1407 Edelbrock on my 440 with 2.96 gears and big tires gives me a few feet of burnout.  Same car with a Thermoquad makes the tires spin into second gear.  Whatever you choose to get, it'll kick Edelbrock ass.

[Cooter]

Let's get real guys, it's a guess as to what carburetor MIGHT work on this engine combination if the owner has not tuned what he has already got.
[/quote]hence the reasoning behind offering a 4bbl verses a 6pack. its the ole KISS theory. Keel it simple stupid

[Cooter]

Yeah, 6 packs are junk..... tell that to my buddy's road runner....
Um nobody said they R junk. I got buddy that runs in the 10s with a honda. Likeyour buddy all it really proves is with enuff tuning anything is possible.

[c00nhunterjoe]

Yeah, 6 packs are junk..... tell that to my buddy's road runner....
Um nobody said they R junk. I got buddy that runs in the 10s with a honda. Likeyour buddy all it really proves is with enuff tuning anything is possible.

The above quotes and replies labled 6 packs as "finicky, hard to tune, unreliable". To me that translates to junk. My point was they are no more difficult than anything else given you know how to work on them. A lot of people lable holley double pumpers as junk because they spit and have off idle stumbles yet they think the only tuning should be the idle mixture screws...... its the same thing. Tune it right, tune it once, and enjoy the ride.

[Musicman]

heyoldguy... you ever have that feeling your  

 

[heyoldguy]

heyoldguy... you ever have that feeling your  

 

Yes, often.

[69wannabe]

Its not that I believe 6 pack set ups are bad, i'm just all for making it work good for minimal money. The holley 750 carbs can be bought for less than 500 bucks. A 6 pack set up would go around 1500 bucks I guess, I really haven't never priced that set up and then you would have to swap the intake and it just seems like it would be expensive and a lot of work if you just want the car running good by just simply swapping to a better 4 barrel carb. But if money isn't a issue and that's what you would like to have then that's what I would go for. I would actually like to try one of the new FAST throttle body injection kits on my 493 but the price tag is a definite kicker and after I recently bought a new holley 850 DP that runs great i'm go to go anyway!! I worked with a guy awhile back that worked with dodge back in the early seventies and he says how the 440+6 engines were stronger than the 375 horse single 4 barrel versions. He knew first hand since he got to drive them and owned a few different mopars in the past. It's all in what you want on top of your engine, The holley DP carbs have won my trust as good carbs and good performance and drivability. I'm sure there may be better performing carbs out there as far as producing more power but if it runs good and moves out good when I stand on it then that works for me!!