1 four barrel vs 2 four barrels

[leon]

Could you tell me if there's a big advantage or difference to running 2 four barrels Tri- power or EFI I have a 351w single 4 barrel with aprox 400 hp
Thanks Guys

[Bernica]

That's a big open question. It depends on your intent on how you want the car to behave and what you plan to do with it. It would also depend on your current engine build and what it can take. Cam specs? I'm sure someone here will weigh in.

[blykins]

I'm not a big multi-carb fan. It's hard to beat a good single-carb setup if everything is chosen correctly.

[DanEC]

Two carbs are for banzai acceleration in a straight line. A single carb (with center hung floats) is for the twisty road courses. Most dual quad intakes don't have enough room for center hung float Holleys.

But I was always more of a straight line guy.

[LMH]

Multiple carburetors are old school. A way of getting more air in. Properly tuned and set up, they work great but they are more complicated. Modern single 4V carb can most likely perform better with less headache but nothing can beat the looks of multiple carbs.
Modern fuel injection in Cobras and Cobra replicas doesn't interest me at all, so I can't really comment on that.
Larry

[Bernica]

I used to have a tri powered 427 in a Galaxie and to this day still get sh%t from old friends about how much time I used to spend working on the setup, which I did.
So, IMHO I wouldn't recommend that for a Cobra.

[wkooiman]

It is mostly visual. An FE looks pretty awesome with 2x4s and S&H air filters. I've run them on 2 FEs now, and they work very well - assuming you get the correct linkage and carburetors.

The only hassle I have right now is a tendency to die when making hard left turns. The side hung floats are much more sensitive to the fuel level in the bowls. It is fixable, but on center hung floats it is a non-issue.

I would probably run a single 4 on a 351W, though. 2 Holleys on a 351W looks top heavy.

[1795]

I searched this same question yesterday as I was bored and needed something car related. From what I cold see it varied from a good 4 barrel being better than dual quads to no difference, to the dual quads having an increase in horsepower. It seemed like the problem that could happen with a dual quad setup resulting in lower power were situations where there was too much airflow and gas for the engine setup. As others have said, it comes down to the quality of the intake manifold, head porting, cam specs and the size of the carbs. You should talk with your engine builder specifically about this.

[Bernica]

A modern custom built 4 barrel with racing floats will do you just fine! There are plenty of good folks that build them. I am partial to Pro Systems, but that is just my choice.

[Tommy]

Leon,
My best advice is for you to listen to blykins advice. Beyond that you have to better describe what you want to get a truly meaningful answer. Rank the following according to what's most important to YOU:

• Looks impress the uninformed at the cruise in.
• Looks impress the knowledgable at the track.
• Starts easily.
• Idles well.
• Gets better gas mileage.
• Easier to setup and maintain.
• Doesn't bog during hard turns.
• Accelerates crisply.
• Accelerates smoothly at partial throttle.
• Accelerates strongly at full throttle.
• Makes the most peak horsepower on the dyno.
• Has the greatest area under the torque curve in the RPM range you plan to use.

What are your top 3 or 4?

[Bernica]

Tommy just nailed it! Nice job!!

[LMH]

8V set up on a Cobra is complicated but would anyone have a Colombo 12 any other way than a row of Webers?
Larry

[Bernica]

OK Larry, you win with that one! Good God!!

[wkooiman]

Speaking from experience running both on the street.

I had a 67 GT500 replica with a 428 and 2x4s.
I still have a 72 Pantera with a single four and for a while 4 Webers (going back on soon).
I still have a Contemporary Classics Cobra with a 428 and 2x4s.
And, of course, I have had several 1x4 Holley equipped cars over the years.

In general, a 1x4 is better at cornering, and it is cheaper. A 2x4 is visually more impressive, but from a performance standpoint, it's not going to make a lot more HP than a properly setup 1x4.

Webers changed my Pantera. It idled more smoothly, and felt like it added 100HP to the bottom end. Of course, it didn't add 100HP, but it felt that way. Gas mileage dropped 4 points.

2x4s didn't change the car very much. It drove about the same, although you could feel the progressive linkage as the second carburetor started to open. I enjoyed the mechanical connection to the engine.

A Ford FE is impressive with 2x4s and S&H air filters. When you look at an FE with 2x4s, you say, "Wow!" When you see a 1x4 with a turkey pan, you say, "Nice!" When you look at a 351W with 2x4s, you say, "What is that?" At least that's my impression. An FE with 2x4s is instantly recognizable. A 351W with 2x4s, not so much.

2x4s are not too much carburetor. They are typically vacuum secondary, so it's like a 600 double pumper, with another 600cfm if you need it. If you don't need it, they won't open. Too much carburetor with 2x4s is a common Internet misconception.

2x4s got good gas mileage on my 428 Mustang. I think I was around 18 or 19mpg (that was a long time ago). When you are cruising, you are only on 1 carburetor, so there's no real difference between 1x4 and 2x4.

At any rate, that was my experience.

[Bernica]

Simple answer...

[wkooiman]

Nice!

[Jac Mac]

Anytime this subject comes up my answer goes along these lines... If Nascar can get close on 900 hp and 200mph in a sedan body out of 358 cu in and one 4 barrel what is the point of any more, as you can probably guess I am not into show and shine!

[Ron61]

I had 2 4s on my 64 Galaxie 427 and I have had much better luck and performance with a well tuned single 4. When going around a turn hard the Galaxie would tend to splash fuel away from the jets and it would stumble, not a good thing in a hard turn. All of my cars since then have had single 4s or fuel injection. The 2 4s look good at car shows but I don't do them.

Ron

[DanEC]

Originally Posted by Ron61

I had 2 4s on my 64 Galaxie 427 and I have had much better luck and performance with a well tuned single 4. When going around a turn hard the Galaxie would tend to splash fuel away from the jets and it would stumble, not a good thing in a hard turn. All of my cars since then have had single 4s or fuel injection. The 2 4s look good at car shows but I don't do them.

Ron

OK Ron - if you managed to starve a 2x4 427 in a "hard" turn with a "64 Galaxie" that definitely establishes that side hung floats are sensitive to cornering.

[Ron61]

Dan,

I did it a couple of times but I had good suspension and that car wasn't made for road racing anyway. When I got my first Cobra and set it up for the road track I just used a single 4 and it worked m great and I never noticed any loss of power either.

Ron

Originally Posted by DanEC

OK Ron - if you managed to starve a 2x4 427 in a "hard" turn with a "64 Galaxie" that definitely establishes that side hung floats are sensitive to cornering.