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Let's say that I have a 289 2-bbl engine. Would changing the manifold and adding 2 4-bbl carbs give me a noticable increase in power? By about how much will my mpg drop? Would this work for all years, or only some? Finally, how difficult a procedure is this (do I just unbolt the manifold and carb, and attach the new ones?)?

I appreciate the help,
Frank
 

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Back in the 50's when cars started comming with dual carbs it was because the size of the carbs were very small, like maybe 400 cfms. the big 392 Chrysler hemi definately needed this to run, even the high winding Chevies. With the big carbs of today, there really isn't need for them...at least on the street. BUT they sure do look nice! I know Edelbrock makes a manifold and carb set up for this. I don't know it it will make more power then a good, modern single carb intake. From what I've read the Edelbrock set up runs well, I have no personal experience with it though.

Chevies.
 

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Whoa, I thought Kyle changed his login.

Personally I think three deuces is the ultimate cool, that and a hot set of webers. I heard the only problem with a dual carb setup is getting them adjusted right. Overcarbing is common with one, so I'm sure having two only magnifies the problem.
 

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From what I understand, it's a lot easier to buy carbs intended for multiple carburetion.....regular carbs apparently are calibrated to handle the idle mixture all by themselves.


Then there's synchronizing them......


And when it's all said and done, one decent sized carb can work fantastic.....


So I guess in my mind, unless you're talking about something like webers, especially in an IR setup, anything else wouldnt be worth it.
 

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A single four barrel will give you better performance, but a dual quad or three deuces will win you more trophies.
 

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Let's say that I have a 289 2-bbl engine. Would changing the manifold and adding 2 4-bbl carbs give me a noticable increase in power?
I'll say no...because chances are you'll never get it to run well enough to get it out of the driveway.

By about how much will my mpg drop?
By 100%. See above.

Would this work for all years, or only some?
It would be just as bad of an idea for one year as any other.

Finally, how difficult a procedure is this (do I just unbolt the manifold and carb, and attach the new ones?)?
Yeah. You just get the right intake, the right carbs, make sure they're getting fuel and have at it.

Seriously, dual 4's on a stock 289 wouldn't run worth a darn. Dual 4's on any 289 would only be for show, not a serious set up for driving the car. A 289 only needs about 500 cfm or carburetion. Alot of us are running 600cfm or so, which is really a bit oversized. That's one small 4 barrel carb.

Phil
 

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A single four barrel will give you better performance, but a dual quad or three deuces will win you more trophies
I agree. When I had my stroker built, I taked to Keith about going with dual 4bbl carbs. He told me that he could make more power with a single quad than dual quads. One carb is cheaper than two, and easier to set up and tune. Convinced me.
 

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Dual 4's on any 289 would only be for show, not a serious set up for driving the car.
Uh Oh...wait 'till rjcruise sees that! :chainsaw:

I can't wait...

rjcruise has a dealer installed type dual quad holley setup on his 289. Dual vacuum secondary 600s in fact. He also has a 294S cam, ported 289 heads, etc. and it pumps out 334 RWHP... :horror: I was really impressed when he told me his latest Dyno figure. Sounds like a bunch of carburation, but his 289 runs really nice and drives well.
 

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Bling! Bling! Bling! Bling! Lookeee here!!! 289 with dual quads....... :D

http://images7.fotki.com/v149/photos/1/115740/1734933/Captured200513000004-vi.jpg

In truth though, they are not meant to be put on just a stock 289, that I will agree with the others on. As far as performance - 335 RWHP and 292 RWTQ - well, I guess my engine is beyond a mild warm over, I wouldn't call it extreme, but it has been worked on to work with the dual 600s. Gas mileage, forget about it, I am basically operating at minimum as a double pumper and when wide open, the word siphon comes to mind. But as far as just looking nice, they do a little better than that. Keeping them synched has not been an issue.

Not saying that duals is the way to go, but there were many factors why I chose this set-up, and with proper blue printing it can be done and decent numbers can be had. And it is sure to start conversation and questions the moment you open up the hood ;).
 

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Bling! Bling! Bling! Bling! Lookeee here!!! 289 with dual quads....... :D
That didn't take long...about a minute. We were probably writing our posts at almost the same time. :highfive:
 

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Oh Really. I beg to differ with you.
 

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how cool is this
Its for an FE but thats just cool.... Probably be one of the biggest pain in the asses though
 

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Nice set-up rjcruise! which intake and carbs are you running? here's a pic of my set-up that I will be using in my 64 Fairlane http://members.shaw.ca/blueoval/int001.JPG
more pics can be seen here dual quad 289

John
 

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Thanks John, yours is not too shabby either ::. Schweet!! Not to hi-jack your post Frank, but rather to add a little more info to your question.

My intake set-up is one of the ones that Shelby American was putting on their competition race engines back in the day. I found a book which is from Hot Rod Magazines 'Great American Engines' series, and in it, it shows my set-up, exactly as it sits on my engine. To add a little more creedance to this, I was able to back-track info (from PO) that the original owner of my car either owned or worked for Shelby American.

The intake manifold is a dual four-throat manifold that is not a a double-runner 180 degree item. Instead, it is designed to act at the top of the rev scale as if it were a true port-per-cylinder unit similar to the four dual Weber setup. The two 600 CFM Holleys are setup to act progressively, transfer passages within the manifold act to give even distribution in the intermediate stages until all eight throtttle bores are open at which point each bore feeds an individual port directly. According to my book, I have Shelby/Ford part number C6ZZ-6B068-A, with R-2804-AS and R-2805-AS for the carbs. Sounds like you have part number C40Z-6B068-E.

Yes, I am certain that modern technology has improved over the last 40 years, but man if I am not a sucker for the nostalgic. That plus the fact that the original owner had this system installed and a few other goodies was enough for me to plan my engine build around it. Can I get better numbers with a single carb and different manifold? Perhaps, but would I just sit there and tell myself how purdy those tow carbs look sitting on top of the engine, wondering what all they have been through - priceless!!

Can't wait to see some more progress pics of your engine!!

http://images8.fotki.com/v145/photos/1/115740/1734933/Montereypics00043-vi.jpg
 

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Sounds like you have part number C40Z-6B068-E
rjcruise
C40Z-6B068-E is the "low rise" Cobra dual four intake that uses carter carbs. C6ZZ-6B068-A is the "high rise" set-up introduced in mid 1966. Your intake and mine are the high rise version. There are 2 different high rise intakes, one with a square runners and the other with round intake runnners. Looking at some of your engine pics, looks like you have the square runner intake. Here are the 2 intakes side by side for comparison
http://members.shaw.ca/blueoval/dual001.JPG http://members.shaw.ca/blueoval/dual002.JPG http://members.shaw.ca/blueoval/dual003.JPG http://members.shaw.ca/blueoval/dual004.JPG http://members.shaw.ca/blueoval/dual005.JPG http://members.shaw.ca/blueoval/dual006.JPG
 

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This post might now be officially hi-jacked... You have not stated this specifically but am I correct in assuming that Holleys cannot fit the "low-rise" intake -- not enough room for the float bowls? I was thining that a couple of Holley 390s might work reasonably well on the street.

- Gord
 

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I would hope you were planing on changing the cam and reworking or replacing the heads first. I would agree that if you just put a dual carb set up on to a 2 barrel motor it would be hard to get the car to run correctly.
 

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Hey John. Huh, didn't know there were two different versions of the high-rise. Yes, looks like I have the one on the 'right' in the first picture. You sure do have some nice stuff there.
 
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