Edelbrock Twin Four barrel Carb info wanted

I am looking at getting a pair of Edelbrock carbies to go on the 318 Poly 57 Fury twin four intake I have. the poly is basically stock, mild cam,stock heads,twin point Mallory.........Originally this intake used the old WCFBs, I was going to get a pair of Edelbrock 1404 500cfm carbies and jet/meter them down, however I have been told that the 600cfm versions can be used just as well, again jetted/metered down..........has anyone had any experience with using these on a twin four intake? I have a mate here in oz that imported a pair with an edelbrock intake for a small block chev and has had nothing but trouble trying to get them sorted out............tho' I think someone had "played" with them without knowing what they were doing.....lol......so I would appreciate any info thats available.......thanks, andyd

 

Have used the same carbs on my 350 chevy for four years now and have had no trouble with them.They were a "Drop" on and fire it up. The linkage sometimes need some adjustment but nothing else. They came with a very good book on tuning but I have never had to open it, Good luck with your change,

 

Jet/meter them down?

You may not have to change the stock jets/rods.
The engine will pull the air it wants and the carbs will respond with the proper - or close to it - amount of fue due to airflow.

Is your mate running a big cam?

Those idle at a low vacuum level and there may not be sufficient vacuum to keep the metering rods down at idle and low speeds.
He may need a lighter metering rod spring.
A set of five pairs is $7. - $8. here in the states making them about the cheapest tuning device you can buy.

Vacuum holds metering rod springs down and the springs raise them up.


There seems to be an old saying that carburetor novices repeat that indicates you can jet a carburetor down for an engine size.

Not so, the Carter/Edelbrock carbs pull the air they want regardless of engine size.
You can get away with running overly large CFM rated carbs if necessary.

We stuck a 750 CFM Carter on my pal's mildly built 302 Ford a couple months back.
A temporary expedient since his 600 CFM Edelbrock sunk the float.
The engine ran fine, a few days later new floats were installed and the 600 went back on.

 

The 500's are expensive. I bought a good used 650 on the site we all love to hate then got the internals necessary to de-tune it to 500 specs. On my 283 it gets 21 mpg.

 

De-tune to 500 specs?

21 mpg is appealing, what kind of car do you have the carb on and what did you do to the carb?

 

Got the twin 500 cfm Edelbrock Thunder series carbs on my 489cid big block Chevy. Ran geat out of the box. I worked the formula and 1000 cfm is about right for my max rpm. Lots of cam & big tube headers. Holley makes a 390 cfm that might be better suited for your application. Holley can probably help you out if you call them for technical assistance. Nothing sucks like an overcarbed engine loading up. Driveability really suffers. Google "carburator size calculator" and be realistic about max rpm and volumetric efficiency. I hope it works out for you.

 

the one thing i like about these carbs are is you can bolt them on and they will run,but they always have a hesitation in them.also if you take your car to the track make sure you have some tuning kits with you.i put one on my amx and took it to the track{16.8 in quarter}that sucked!!!changed the metering rods and it went 14.8{better}that was as fast as i could get it.i then put a holly 750 doubble pumper on it and got it down into the mid 13s.so if you just want it to run use them but if you want it to run fast buy a holly.

 

A method I've seen to calculate indicates a 318 needs 500 CFM, div by 2 carbs is 250 CFM each! I talked to the Edelbrock guys about this, 2X4 on a 318, on the Power Tour this tear. They said if you contact them & give them the details they can set it up so it'll run right for your set up. I guess you can do it or have them do it, depending on your abilities.

 

No idea what American Opel is talking about on a hesitation. i have installed close to 30 Edelbrock carbs and only had an issue with one, and it was a faulty carb that Edelbrock replaced for me.
I currently run a 500 on my 302 Falcon, a 600 on the 347 in the 34 coupe, a 600 on the aluminum head 302 in the RPU, a 600 on the 383 in the COE and a PAIR of 500's on the 302 in my 32 Coupe. Noe of these showed any hesitations.
The dual carbs on the 302 ran excellent out of the box and a little tuning dialed them in perfect. I use the Edelbrock progressive linkage and It runs great - no worries
The Falcon with the 302/T5 and 3.0 gear gets 23 MPG on the highway with the 500 on it.

 

Both of this Site will answer every question you have about the 1404's...

http://www.edelbrock.com/automotive_new/misc/tech_center/install/1000.shtml[/URL]

 

C9, my de-tuned 650 Edelbrock sits atop the 283 in my '36 Ford Tudor sedan that has a Turbo400 and 2.88 8" rear. It has been a while, but I just found the specs and parts list for a 500 and plugged those parts into the 650.

 

really not a problem to set up but it takes alittle time. Start by dropping the accel. pump linkage down to the bottom hole , then pick up 2 step up spring kits. The carbs will usually come with the longest springs installed. If it's running too rich you can drop the spring size down like 2 sizes and then set the whole thing up again. You may have to play with it for a while to get it where you want it . Small changes on each carb can do alot so take your time and have fun with it

 

Sounds like you don't have a handle on tuning the Edelbrock's. Don't blame the carb. Of course you said nothing about the specs of the engine, nor the carb you tried. Usual Edelbrock bashing BS>

 

I agree........ I have twin 500 on my 350. Pretty serious cam and high stall converter. After I set up the carbs, it runs perfect, NO HESITATION, and gets pretty good mileage and is GREAT in traffic. But then who's worry'in about mileage and runnin' 2 fours?

 

I have a Summit set up that comes with 2 500cfms on a 347 Ford and it works great Eldebrock makes 500cfm carbs that are made for 2 4s so they say Hope this helps Pony Express

 

you know what zman you can go *&%$##$%^^& your self.all you do is bash everyone on this site!!!!!!!!!!if you want to help start doing paint jobs for free!!!!you charge a million for" your guys to paint cars for people so you can sit on the computer all day and criticise people for what they say or do and im sick of it "{and so are alot of other people}so next time you want to get another post under your belt make sure you give some help not bullshit!!!!!!!

 

they are fine to run them on a street car only problem i have with edelbrock carbs {and MOST PEOPLE I HAVE TALKED TO}is when you floor it they always go??????????????????whamp-whaaaaaa.{trying to make the sounds come out as words.LIKE I SAID BEFORE.they are good carbs if you just want to put them on,but if you want to go fast then they arnt the carbs to run!!!and yes i know how to tune them!!!!!!!!!!!!!the problem with them is the metering rods...yes it is a good setup but you have to wate for the vaccume of the motor to start to pull the rods up to make it run richer{this causes LAG}thats the reason i dont run trhem on a drag car{but there fine on the street}

 

like i said before if you want help,let us know what you want to do with your car!!if you want to just drive it than 2 600 will work,but if you want to drive it and also get the most out of your car lets talk and i will help you.i will need to know what kind of car,{weight,cam spec.comp.gears.trans,and what you want to do with it}

 

Would like to thank everyone who has replied, I've learnt a bit.....the car is my 1940 Dodge Sedan, it runs a 318 poly, basically stock.........if I had a choice I would rather run a pair of Holleys BUT they will not fit on the factory cast iron intake which originally had WCFB's........and thats why I have to run a pair of Edelbrock carbies.....I have tried to phone a couple of numbers I have for Edelbrock, however they ring out, also as I am in Australia its difficult to obtain local info on these.........when I first rodded the Dodge in the mid 70's I had another cast iron twin four intake and after playing with the WCFB's for a while I got a pair of the old Offy bolt on cross ram adaptors and used them with a pair of 600 Holleys sitting above each poly rocker cover......with a 35/75 cam, Hi stall converter etc it scared the crap outa me..........so I sold the intake,Offy cross ram adaptors, etc and have been running a single 600 Holley on a Weiand alloy intake...........I know, I know........this is the best all round street setup but I'm in my mid 50's and would like to relive my stupid youth...........lol..............anyway any more info will be gratefully received..............regards, Andy Douglas

 

Hunh? a million really? I'm rich I tell you rich....

as C9 has said and so have others, softer springs, the pink ones most likely. Then it takes less vacum to pull up the rod, hence less lag.

 

Carburators and politics bring out the best in some people. I ran a pair of 500cfm edelbrocks on a tunnelram on a decent 327 motor, non-progressive linkage and had no problems, other than making sure i was pointed nice and straoght when i stomped it. Wasn't the best on mileage, but then its a hot rod.

 

Am I correct in thinking the 500 and 600 carbs have the same butterfly bore sizes and a change in boosters or any other air flow impediment is what the difference between 500 and 600 amounts to?


I think my 32 roadsters mpg problem is mainly one of aerodynamics.

Along with that, a couple of times I got into tuning for mileage they changed the gasoline formula.

And I still haven't had a chance to check mileage on a long and reasonably flat chunk of highway.

After I went to the 3.00 diff (from a 3.70) - 30" diameter rear tires - the car improved one mpg on the run down the hill to Laughlin, Nevada.
Not a particularly great place to check mpg with a 6% grade for 12 miles....

 

When I was building the 396 for my Vette I went on the Edelbrock site and found a help line, gave them the particulars, and they E-mailed me back the next day saying that they recommended the 600's and also told me what jets and metering rods to run. I then contacted them back and had them send me the parts. It was simple and expedient. Surprised me that they did'nt recommend the 500's.

Engine specs; .030" over 396, TRW forged pistons with stock dome configuration, round port heads with open chambers, drops compression ratio about a point (say 9.25) reroduction L88 solid lifter cam, four speed, 3.31 gears, 3000#.

 

I run a pair of factory 600's on my mild 455 without any problems and then I experimented with the rods and jets to see if I could improve the mileage without success.

Changed the linkage to a progressive and went from 12mpg to 14 mpg!

On a small engine the factory setting with a progressive makes sense... again it's nice to know the specifics of the car... such as the gear ratio, tranny type, tire size and weight.

What specific altitude will you be running at??? Mountain settings are different from sea level.

As these factors will drastically effect the performance and economy.

I got the performance I've wanted but all my economy came from other sources than the carbs...

#1... Progressive linkage
#2... Overdrive Transmission
#3... Different size and style of tires

When all was said and done... I've squeaked out 20 mpg twice but .. I've been happy with the improvements making the car a bit more affordable to drive daily with 17 + or - mpg with the Edelbroch factory settings!

 

32 Ford roadster.

462" Buick (.030 over 455).

Very mild cam.

Performer intake manifold.

Single 750 Carter, jetted/rodded for 3400 altitude where I live - runs good
down at the river which is 500'.

3.00 diff gears.

30" tall rear tires.

2400 rpm at 70 mph.

2400# wet sans driver.


A few years back I pulled the straight linkage dual quads for the 31 on 32 frame roadster project and installed the single 750 on the 32.
Mileage went up 1 mpg in town and the same on the highway.


Jetting the 750 was done following Edelbrocks recommendations and is two steps lean.

Done because the car formerly lived in Central California at 350'.


Interesting find on gaining mpg by swapping to progressive.
I've been thinking of making a progressive linkage setup.

Probably after the car is up and running....

 

And worst???

It is not at all unusual to find individuals that have had good results (at least initially) with the clones; as well as individuals that have had terrible results with the clones. And this is not a statement concerning the tuning ability of any individual.

<O</O
One simply needs to do a little research to understand.
<O</O

When Carter was still in business, Carter produced 505 different AFB carburetors. This figure does not include carburetors with major engineering changes, which required an edition number change (i.e. 3720s -> 3720sa -> 3720sb – the letter representing a major engineering change, but not sufficiently major to require a new carburetor number).
<O</O

Within the 505 different carburetors, Carter offered a unit from 400 CFM to 950 CFM for virtually every engine/transmission/weight combination up through the 1965 model year. However, by the time the Chevrolet 350 entered the market; Chevrolet was using Q-Jets on most applications, and Holleys on applications that had a good probability of being raced. Chevrolet was not using AFB’s. As the 350 quickly became the most popular “hot rod” engine, Carter started offering aftermarket or “performance” carburetors FOR THE SMALL BLOCK CHEVROLET!!!!! There was absolutely zero need to offer any other aftermarket carb; as Carter had original equipment carbs for all other common and most uncommon applications. Original Carter sales documentation stated, “these carburetors are calibrated on a xxxxxx, the purchaser is responsible if they are used on other applications”.

In the mid-1980’s Carter was purchased by Federal Mogul; who revised the design of the AFB in order to be able to make (and thus sell) the unit for a lower price. These revisions (my opinion, others may differ) did not help either the drivability or reliability of the units. Federal Mogul continued to offer aftermarket carburetors with the Carter name and the same number, but an edition letter change to differentiate from the real Carters.
<O
All of the clones, regardless of the name on the carb, are basically these same revised small block Chevrolet calibration carburetors.
<O
So why do some have initial good luck with the clones and others don’t?
<O
The calibration for a “screamer” engine (i.e. SBC) is TOTALLY different than one for a “torquer” engine (i.e. Pontiac 389). The calibration differs in many respects; but the two major issues involve step-up rod profile (the SBC rod may have a “delta” of as much as 0.024, while the Pontiac rod may have a delta of less than 0.010); and the attack angle of the auxiliary airvalve plates (the SBC plates have a much more aggressive angle). The more aggressive angle allows the airvalve to open sooner, causing a hesitation with torquer engines (Chrysler, Olds, Pontiac, FE Fords, etc.).
<O
Carter did not produce 505 different AFB’s simply to keep the engineers and foundry employees busy; and remove R & D money from the profits of their investors.
<O
If you truly believe “one size fits all”, try walking a mile in your spouse’s shoes.
<O
What one gets out of a carburetor has much less to do with the make of carburetor (although this is an issue) than selecting the proper (size and style) carburetor for the specific application, and understanding of the circuitry of the selected unit.
<O
And always remember the ABC’s of carburetion: (A)lways (B)uy (C)arter. &#9786; &#9786; &#9786;
<O
Jon.

 

I have a pair of 1404s on my hot little SBC with an Offenhauser 360 intake. When I had my engine dyno'd they weren't able to hook up the A/F meter so they tuned off the HP gains or loss. It was a little fat (at WOT)so they just dropped the jets in the secondaries to compensate (they left the primary rods, springs and jets stock.
When I put my car together I called Edelbrock to get some basic help.... this was for nothing! They were no help at all.
Anyway, to make a long story short. I did what most people do (wrong) and jetted down my primaries thinking because I had more CFM than I needed that jetting down would help. Don't do this - you can't jet it down to compensate for too much CFM.
I'm back to an almost stock settings and it runs great. I'm going to put it on a chassis dyno to do some final tuning later.
Anyway - all that to say.... bolt them on and have fun! Get two tuning kits and adjust from there.

 

Generally (not always) too large a carburetor will run LEAN (decreased air velocity); not rich. Too small a carburetor will run rich (increased air velocity) up to a certain RPM, and then fall on its face.

Jon.

 

This make sense! I probably need to make mine a little fatter. Because my motor is not turning on like it should, it's a little sluggish (in my opinion). I wonder why they thought it was too fat when they dyno'd it?
I went to a fatter rod on the primary carb, in cruise mode. It stopped all the lean popping when I get off the throttle. Do you think I should do the the same on the secondary carb?

 

Brewton . . . fatter rod meaning larger or richer?