MARKUS_P

Saw an edelbrock twin carb setup lately in a cataloque.
Now my question:
Two carbs will be able to get more fuel / air mixture down the intake as one single carb (assuming the same cfm -rating)
As I understand itīs only for a very radical high output engine, or is the real advantage that two smaller carbs react better than one big one?
Further more Iīm curious about the flow ratings of such an intake.
Can it compete with the performer-rpm intake?
Thanks, Markus

MassVette

The long-time accepted consensus (on American V-8's) is that one big carb is better than two smaller ones.
That being said, I can tell you that the Edelbrock dual quad setup on my ZZ/502 runs better, has more low and middle-end "grunt", is more reliable, and gets better mileage than the 780 Holley or the 850 Demon that I previously had installed on it. Of all American carburetors I know of, the AFB-style carb seems to hold a setting better than the rest- and also has mechanical secondaries.
My 2c.
:yesnod: :chevy :chevy :yesnod:

gkull

I've only personally run two four barrels only once. I went from an 850 double pumper on a victor jr to a tunnel ram with twin 660 cfm center squirter Holleys. It was faster in the 1/4 mile and really ran well. But when I shifted away from drag racing I installed twin 450 cfm Holley four barrels. That really made it a nice running street rod.

My next door neighbor had a twin Edelbrock 600 low riser setup and he swears by it. He's been driving it for 5-6 years (67 Chevelle factory 427). The low rise with 2X4's with smaller cfm carbs and vacuum secondaries would really work well on a small block and not to radical of a cam.

The real advantage that I can see to twin 4's is very even fuel distribution. In the last 5-6 head changes that I've done on my Vette and this is with all single plane intake manifolds. The inner four cylinders had darker carbon build up on the pistons. Which would indicate that they run richer than the outer four cylinders

Markus - my Teresa was back home in Austria in August just in time for the big floods. She said that it was really sad in the western part where she was. She flew back just in time for us to go to the BurningMan Festival in Sept. I hope that you and your family were not hurt by the flooding. :seeya

ram82fire

Being a really old geezer I am a fan of multiple carbs, I am currently running four two barrel side draft webers on an independent runner system . I know from experience that you can get more power from a single four barrel on the right manifold . I,m a dedicated tinkerer and enjoy it . Each and every system has its drawbacks , I really enjoy great driveability and good performance . Carb configuration is a bit like eating sushi ,,,,,,,,,, its just not meant for everybody .

Geo :crazy: :crazy: :crazy:

Wrencher

I'm another multiple carb fan, but it depends on the application. For drag racing, a 2x4 tunnel ram works great, but it's useless on a road course or the street. For road racing, use a single four barrel oe F.I. On the street is where you can use small multiple carbs for the cool factor and still have a driveable car, as long as you don't mind generally worse mileage. I run 4 carbs with a progressive linkage on my Corvair and like it a lot.

Hans

Solidlifters

I've long been a fan of the 2 4's on the inline intake like MassVet has in his picture. I've even got 2 straight axle cars with a similar setup, except for much smaller intake runners and the old WCFB carbs and an Edlebrock/AFB set up on the shelf. I don't think there's anything cooler looking than these set ups. Ford had some of the best looking ones around in the 60's with at least 3 different height intakes. There old "high riser" 427 may have been one of the best lookin' motors ever built by anybody.

Now the bad part: One of the magazines ran a comparison of intake/carb combos within the last year and the old inline 2 4's were among the very worst performers. The horsepower loss they were showing was pretty amazing, although I don't recall the exact numbers. There's a lot more to opmtimizing fuel charge than just the CFM rating of the carbs. That's the reason that a well tuned 66 427/425 Corvette will always turn better times than the later tri power cars, even though the tri powers had CFM ratings of 1050. It's also the reason that GM chose the single Holley rather than the tri power or 2 4's for the L88's and ZL1's.

As a side note, in the late 60's I bought an STR10 Edlebrock intake, which was the aftermarket knock off of the Z28 crossram. I broke the motor in my car the week after I bought the intake and carbs and never really got a feel for it. There was a local guy that had a Yenko Deuce (basically a Nova with an LT1 from the factory) that had it running pretty good at the drags. Some time later, I ended up selling the 2 4 set up to him. In spite of carb changes and gobs of tuning it ended up being .5 slower and he finally abandoned it.

Back to Fords for a second, my 67 500 Shelby is the only year that these cars came with 2 4's when new. In 68, the car had the stock 428 Cobra Jet with the 735 Holley and was reportedly faster. In all fairness to this comparison, the CJ motor also had some other components making it a better performer, but it would've been right in Shelby's line to stay with the 2 4's if there was a performance advantage there.

MARKUS_P

Thanks for all this information, very interesting.
George, thanks for your request concerning the flood.
We were lucky that the vienna government decided years ago to build an emergency river bed beside the danube.
So they could open it up when the flood came and no one had to suffer near vienna. My girlfriends parents have a cottage in the north and they were even more lucky because the only reason why they wernīt flooded was that they built their house on a little mountain.
I was in the affected areas and saw the damage of the flood.
It was unbelievable. Streets were swimming away, bridges broke down, the rivers found their own new bed, in some cases right through the municipalities.

'79ProwlerOrange

markus, you need to update your sig! :lol: