Single or dual carb?

Lew Ledyard · #1 (**permalink**) 07-31-2006, 08:33 PM

I like the look of the Stellings & Hellings air cleaner (with a K&N element). However, we all know that you cannot flow nearly enough air through one on a BB, especially the larger displacement high performance BBs that are made today. My understanding is that a single carb is easier to live with and is more driveable than a dual carb set-up. However, if my goals are to keep a somewhat stock or period look (not necessarily 100% accurate, but I don't want an Xtreme lid or an 18" filter), to get great performance and driveability, and have a motor that stays in tune (I want to drive, not tinker), should I go with a dual carb set-up with S&H air filters (and K&N elements) since two small filters should flow twice as much air as one small filter,or just stick with what I have?

I have a KC 482 ci Shelby BB with a single Pro Systems carb that makes about 630 hp/tq. It drives really well currently and I don't want to mess that up. However, I am not sure what I am missing, so I am not sure if doubling the air filter area will make things even better. I also want to keep the stock KMP hood scoop.

Thanks

Anthony · #2 (**permalink**) 08-01-2006, 05:24 PM

Don't nascar sb's make 750+ HP with a single carb?

scottj · #3 (**permalink**) 08-01-2006, 05:50 PM

Quote:

Originally Posted by Anthony

Don't nascar sb's make 750+ HP with a single carb?

Most are closer to 850 these days and now that they're getting the new D3 head figured out the Fords guys have reported 860.

Naumoff · #4 (**permalink**) 08-01-2006, 06:54 PM

Quote:

Originally Posted by Lew Ledyard

I like the look of the Stellings & Hellings air cleaner (with a K&N element). However, we all know that you cannot flow nearly enough air through one on a BB, especially the larger displacement high performance BBs that are made today. My understanding is that a single carb is easier to live with and is more driveable than a dual carb set-up. However, if my goals are to keep a somewhat stock or period look (not necessarily 100% accurate, but I don't want an Xtreme lid or an 18" filter), to get great performance and driveability, and have a motor that stays in tune (I want to drive, not tinker), should I go with a dual carb set-up with S&H air filters (and K&N elements) since two small filters should flow twice as much air as one small filter,or just stick with what I have?

I have a KC 482 ci Shelby BB with a single Pro Systems carb that makes about 630 hp/tq. It drives really well currently and I don't want to mess that up. However, I am not sure what I am missing, so I am not sure if doubling the air filter area will make things even better. I also want to keep the stock KMP hood scoop.

Thanks

Lew, Don't mess with something that ain't broken.

Burgs · #5 (**permalink**) 08-01-2006, 06:59 PM

Quote:

Originally Posted by Anthony

Don't nascar sb's make 750+ HP with a single carb?

But they're not using a single Stellings air filter,...

Lew Ledyard · #6 (**permalink**) 08-01-2006, 07:05 PM

"Don't nascar sb's make 750+ HP with a single carb?"

Not with the 8" Stellings & Hellings air filters.

I am not trying to determine whether a dual carb set-up makes more power than a single carb set-up in general. I am looking for guidance as to whether a dual carb high performance big block motor with two Stellings air filters makes more power and is just as, or even more, driveable than a single carb big block set-up with one Stellings air filter (with all else being equal).

It seems one argument for a dual carb set-up might be a way to keep the Stellings air filters (for those of us who like that look) and allow a little better breathing (since there are two small filters rather than one). I am curious as to whether there are any trade-offs.

Lew Ledyard · #7 (**permalink**) 08-01-2006, 07:18 PM

Quote:

Originally Posted by Naumoff

Lew, Don't mess with something that ain't broken.

That's very good advice that I should follow.

dblbarrel · #8 (**permalink**) 08-01-2006, 07:32 PM

Lew:Yes that is very good advise, and you should follow it. I have a feeling you wont.

jaxssnake · #9 (**permalink**) 08-01-2006, 07:53 PM

Lew; I am using a 2x4 setup that I purchased from Carl's Ford Parts in Ohio.I believe a good single carb makes as much if not more power.I chose this induction system for the right look. I have no regrets as the car idles smooth,pulls hard with no coughs or stumbles. Check out my photos,I am also running stellings with K&n filters. Regards Jack

Naumoff · #10 (**permalink**) 08-02-2006, 04:55 AM

Lew,
I went with the 2x4s for the look. That being said I have not touched my carbs with 6000miles on the Cobra and regularly make milk runs aswell as cruises.

If you go by all the calcuators for sizing carbs for your engine 2x4 1200cfm is to much.

Excaliber · #11 (**permalink**) 08-02-2006, 10:45 AM

I think the sizing calculators for carbs are a lot like the drag race calculators for cars. An interesting guideline, not to be taken to seriously. Real world conditions, in many cases, just cannot be reconciled with the carb calculations.

1200 cfm, all though a bit small, will work. 1350 would be 'just right'!

Seriously, it IS true that in plenty of cases for 'street' car over carbing is a common problem. I'd rather be 'rich' than 'lean' however.

During the GT-40 days when Shelby needed more horse power he went to a 2X4 setup. A single four is the best call for easier tuning and engine management, it's not always the best call for horse power.

lineslinger · #12 (**permalink**) 08-02-2006, 10:56 AM

The dual quads do look nice, mine is set up for primary running on one carb only, but the second can be brought into play quickly, and must be done so carefully.
The other picture is the K@N dual quad filter, I lost about 7hp using this filter as opposed to no filter at all.

Naumoff · #13 (**permalink**) 08-02-2006, 01:35 PM

Nice engine Lineslinger.

Ernie

lineslinger · #14 (**permalink**) 08-02-2006, 08:24 PM

Thanks Naumoff...you too man.

cleandan · #15 (**permalink**) 08-02-2006, 08:30 PM

Lew, because you like the Stellings air cleaner look and want to stay with it have you ever thought of making your own air cleaner that replicates the Stellings, but a bit larger?
Find a shop, or do it yourself. I see a sheet of SS used for the top and bottom (able to polish like chrome without the hassles of chrome wear). Form the top to look like the Stellings yet make it larger for your needs and match it to an easily attainable air cleaner element that fits the needs too. Just an idea.

maurice19 · #16 (**permalink**) 08-02-2006, 10:31 PM

Lew.

I have the Stellings on 2 660`s sitting on a tunnel wedge intake.

Seems to make good power up to the chip at 6500.

I like the look and the feel of the acceleration they provide, and don`t notice any breathing problems.

664 hp at 5800

Go for it,
Maurice Lawrence

Lew Ledyard · #17 (**permalink**) 08-07-2006, 09:00 PM

Maurice:

Did Keith Craft provide the dual carb set-up?

Thanks,

Lew

BOURRET · #18 (**permalink**) 08-07-2006, 10:40 PM

I have a Keith Craft 428 with two four barrels Holleys ( 2 X 600 cfm) equipped with a single big oval filter (Green K/N)

maurice19 · #19 (**permalink**) 08-08-2006, 09:27 AM

Hi , Lew

Yes, Keith did supply the Dove manifold and engineered the fit to the heads and installed spacers as he saw fit to make it all work.

Maurice

speed220mph · #20 (**permalink**) 08-08-2006, 09:47 AM

Lew: Another considered when choosing 2X4's versus a single four-barrel doesn't have anything to do with performance or looks, but with insurance coverage. A lot of insurers, justified or not, won't insure a Cobra or other performance cars equipped with multiple carburetion.

Check with your insurance man, then go with curb appeal if 2x4's are no problem. Them dual fours sho' do look good.



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