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View Full Version : Fuel System: 500CFM or 600CFM on 289 V8



Reo28
07-16-2011, 07:58 PM
Hi All. I am about to fit a 700R4 using a Fairborn adapter behind my 289 in a Silver Hawk. Currently use a WCFB carb and can't find any info on setting up the TV cable from the trans for this carb. I am thinking of fitting an Edlebrock carb and wonder if I should use the 1403 500CFM carb or the 1406 600CFM carb? I know that the 1403 is designed for small V8s up to 305 cu in, but wonder if the 1406 rejetted with leaner jets might be better as less throttle may be used hence as good if not better MPG. I do know that I will have to machine my inlet manifold to match the larger throttle bores of the Edlebrocks. The wise advice of you all is appreciated. Cheers Mal (from NZ).

Mike Van Veghten
07-16-2011, 08:36 PM
This subject is huge if you just go into the "search" area. You'll find many hours of reading.

In short...will a 600cfm carb. work..yes. Will an 850cfm carb. work...yes...it actually will.
But if you plug into ANY of the carburetor vs. cubic inch size charts....just what you've already noted, the 500cfm carburetor will provide the best power/milage of most any out there. Actually, a 450 might work a little better, but there isn't many out in that size. The 500cfm carb. is actually just a tad too large...and that's with 100% volumetric effiniency...which "most" if not all but the top 1% Stude race engines deliver. You can figure maybe 80% efficiency for a good used Stude engine.

And no, "just" leaning a jet will not change the charactoristics of air flow...! Never has, never will. That's not how airflow in a carburetor works. You actually need to buy the correct ventury size to begin with.

Go with the 1403 (500cfm) carburetor, your engine AND you...will be happier for it.
The newer AVS, Thunder carburetor, while more expensive also has more adjustability if you like "playing" as some of us do.

Mike

DEEPNHOCK
07-16-2011, 09:01 PM
Well said Mike...

sals54
07-16-2011, 11:53 PM
Mike knows his business. Listen to him and you'll be much happier. Remember, the 600 cfm is usually cheaper but thats just cuz its the most popular. Don't be fooled. Get the 500.

santa
07-17-2011, 01:03 AM
Agreed too.
I put one on two weeks ago and it is a completely different, and marketly better, car. Does not run like a worn out tractor any more. 500 cfm Edelbrock is just right.

Reo28
07-17-2011, 03:34 AM
Thanks guys. You have confirmed my thoughts that 500CFM would be best. Mike your feedback and explanation is appreciated. This is such a great forum where you get very quick responses from people who have 'been there done that'. No point reinventing the wheel I say, when there are knowledgeable folk who can help.
If anyone reading this has done this swap with a 700R4 and still used the WCFB carb, I would love to correspond with you. Cheers Mal

Mark57
07-17-2011, 01:35 PM
Just put a 1403 (500 cfm) on a 259 V8 equipped Champ pick-up last weekend and it runs like a top. As Mike mentioned, anything smaller is almost impossible to find. :)

PackardV8
07-17-2011, 02:37 PM
Hi All. I am about to fit a 700R4 using a Fairborn adapter behind my 289 in a Silver Hawk. Currently use a WCFB carb and can't find any info on setting up the TV cable from the trans for this carb. You can use the WCFB or either of the AFBs, IF you go to 'BowTieOverdrives at www.bowtieoverdrives.com/ and pay them what seems like too much money for their linkage and instructions.. Then, whichever carb you choose, it will be right.

FWIW, I'm an experienced shadetree and I couldn't get the 700R4 linkage right on my own. As a practicing CASO, I was determined to do it myself, but I wasted a lot of time and ended up paying their price anyway.

jack vines

Reo28
07-17-2011, 04:14 PM
Thanks Jack, from yours and other replies, sounds like the 1403 is the way to go. I will still have to get a TV linkage kit from Bowtie ODs for the 1403, but are you saying the WCFB linkage kit is much more expensive than the 1403 kit?
Mal

PACKERBACKER
07-18-2011, 01:17 AM
http://www.motorsforum.com/studebaker/AFB-spec-s-found-on-the-net-6923-.htm This thread by John Poulos shows the R1 and R2 factory carb was rated at 625 cfm. I see that if you use a carburetor cfm calculator that it shows using a 1403 should work fine. Jim Pepper recommends and everyone else that I know that owns an Avanti that changes over to an Edelbrock carb uses a 1406 if they have an R1 or a 1407 for an R2. Now is this ok to use the larger carb because of the Avanti's higher performance output even though it does not agree with a cfm calculator. or does it mean that Studebaker did not know what they were doing and that some of the other experts that call out using the 600 cfm carburetor are wrong? I am not trying to be a smart ass, I am just trying to see who is right!

Mike Van Veghten
07-18-2011, 09:38 AM
Packer -

As the clock moves on...so does experience and knowlege (hopefully).
Not that the 1955 Stude engineers didn't know what they were doing...they just didn't know more thAn people know today..!

Are you old enough to have been around in 1955 ? What doctor would you like cutting into your body....someone from back in 1955 (via time machine)...or someone from 2011. Not saying all doctors, just as designers are equal...but time, experience, experimentation, knowlege...rolls on.

What was the maximum speed a piston driven car could obtain in 1965 in the quarter mile ? I guarantee you it wasn't over 320mph..! They weren't to 200mph yet..! Again, experimentation, experience, knowlege.

So yea...to answer your question, for a stock 259, 289, R1, R2 Studebaker...the 500cfm carburetor is more thAn enough. Even a mildly worked over Stude engine.
Go back and reread my first post. I'd bet that if I played enough, I may even be able to get a Holley 1050 Dominator to work on a 289 Stude engine.
That does NOT mean that the engine will run as good as it could run.

And yes, I have tried several different sized carburetors on my 259 Lark...an old worn out 500cfm Edelbrock is back under the air cleaner..!

Hey...it's your car, it's your gas money, it's your driveability...do as you see fit. I'm not telling you what to do, I just relaying the current, and well thought out by many people....and the "math" what works.

Mike

DEEPNHOCK
07-18-2011, 10:05 AM
All that, and the fuel is way different today, as compared to way back then.
And technology does not stand still, so you can't really say that what was engineered way back then should be locked in stone as gospel.
Those numbers were selected to get the Studebaker through, and out of, the warranty period with the least cost to Studebaker.

What has been posted here is current experience, using currently available Edelbrock carbs, on currently running Studebaker engines, running on current gas.
If somebody can bring more current info...Bring it on!:p
Jeff:cool:

PackardV8
07-18-2011, 11:10 AM
Jim Pepper recommends and everyone else that I know that owns an Avanti that changes over to an Edelbrock carb uses a 1406 if they have an R1 or a 1407 for an R2.It could also be most CASOs can't bring themselves to special order a #1403 500 CFM and pay $319.95 plus shipping when their local FLAPS has the #1405 600 CFM manual choke remanufactured version as a advertising loss leader for $229.99 plus tax.

jack vines

PACKERBACKER
07-18-2011, 01:09 PM
Now I'm even more confused. Looking at http://www.carburetion.com/calc.asp using a 289 engine that max's out at 6000 rpm in stock form you get 426 cfm required, for a mildly built engine 476 cfm. Now if you look at http://www.edelbrock.com/automotive_new/misc/tech_center/install/tech_disc_cfm_rules.shtml Edelbrock tells you that you should usr a carb that is rated 110 to 130% of the required cfm of the engine requirement for maximum performance. If you take the 426 cfm and figure out 110% a 500cfm carb would work fine, using 130% or even 120% it is slightly higher than a 500cfm carb puts out. For a slightly modified engine, like an Avanti, the numbers look like the 600cfm carb is closer to being correct. Am I missing something, or is this not true?

Mike Van Veghten
07-18-2011, 01:28 PM
We could drag this on for years.

And to see any Stude engine in most Stude cars today running to 6000rpm...can you spell "figment of someones imagination". Maybe...a fresh, high dollar, very carefully assembled Stude engine. Most will stop at about 5000.

Plus you gotta note reality...just how long (in seconds) do you plan to spend at this imaginary 6000rpm ?

As noted, do as you see fit, it's your engine. Like I said above, an 850 Holley will bolt on and work also.

Now...just to throw in some more confusion...after all my professing above...I've got a brand new 700CFM Quick Fuel carburetor waiting for my Conestoga's 299 engine to be completed.
BUT, I've also got a lot of rear end gear, a 2.9 first gear trans. being built, a LOT of cylinder head work, a one off (well maybe three) intake manifold (that nearly matches the heads flow wise), over 10 to 1 compression...AND...hoping to come up with a cam shaft with over .400" lift...
EVERYTHING...is a combination. If you don't have everything working well together...well, there goes the driveability, power, milage AND money fer nuthin.

Unless you are racing at Maxton or Bonneville...well you know.

Mike

pdrnec
07-18-2011, 01:29 PM
Set up a 500 as specified in this link and you'll be happy. Car will run well.

http://www.studebaker-info.org/TW/tw0207/tw0207pp25bl.jpg

That's exactly what my 259 wound up with, checking stats with an A/F meter. Fuel economy? Around 16 MPG highway running at 70 - 75MPH. Plugs have a nice light color. Oh, fuel economy is around 20MPG if I go by the speedo mileage instead of the GPS.

DEEPNHOCK
07-18-2011, 01:42 PM
Quit reading too many books.
Studebaker guys here that have done this hundreds of times are telling you their real world experience.
If you are going for mileage, and around town driveability...Go with the 500 cfm.
If you want a sporty deal, with good high rpm and expressway performance...get the 600 cfm.
If you are the purist, why are you swapping at all?:rolleyes::confused:
Those books and charts are general.
So are the carb rod/jet/spring combo's.
Every AFB should be 'tuned' to the particular Stude it is riding on.
There is no 'perfect, out of the box' AFB for a Stude.
You are asking good questions that have no black/white/yes/no answer.




Now I'm even more confused. Looking at http://www.carburetion.com/calc.asp using a 289 engine that max's out at 6000 rpm in stock form you get 426 cfm required, for a mildly built engine 476 cfm. Now if you look at http://www.edelbrock.com/automotive_new/misc/tech_center/install/tech_disc_cfm_rules.shtml Edelbrock tells you that you should usr a carb that is rated 110 to 130% of the required cfm of the engine requirement for maximum performance. If you take the 426 cfm and figure out 110% a 500cfm carb would work fine, using 130% or even 120% it is slightly higher than a 500cfm carb puts out. For a slightly modified engine, like an Avanti, the numbers look like the 600cfm carb is closer to being correct. Am I missing something, or is this not true?

PackardV8
07-18-2011, 02:12 PM
Edelbrock tells you that you should usr a carb that is rated 110 to 130% of the required cfm of the engine requirement for maximum performance. Yes, if it is a professionally built dyno engine and want the maximum horsepower number for a magazine article.

No, if the car is going to be driven in the real world with an air cleaner and mufflers and 99% of the time below 3,000 RPMs.

Maybe, when we understand 99% of all Studebaker V8s make peak horsepower below 5,000 RPMs, reality sets in. When we count up how much money it costs to build a Studebaker engine which will actually make peak horsepower at 6,000 RPMs, the total gets high in a hurry.. When I get inquiries and explain about the $2,500 in head porting and the $350 intake manifold, $350 exhaust manifolds, the $1000 cam, valves and valve springs, the $2500 short block, the $450 aluminum flywheel, all of a sudden, max power at 6,000 doesn't seem so important to most CASOs.

jack vines

PACKERBACKER
07-18-2011, 04:11 PM
Just to let you know where I am coming from. My R2 Avanti has heads with R3 Valves, I had the heads opend up behind the valves, using the stiffer valve springs from Fairborn Studebaker, smoothed out and matched the ports and it has 1.75 ratio roller rockers from Ted Harbit and an aluminum intake manifold. It is pretty fast!

studegary
07-18-2011, 04:28 PM
Just to let you know where I am coming from. My R2 Avanti has heads with R3 Valves, I had the heads opend up behind the valves, using the stiffer valve springs from Fairborn Studebaker, smoothed out and matched the ports and it has 1.75 ratio roller rockers from Ted Harbit and an aluminum intake manifold. It is pretty fast!

That gives you more room for intake. I hope that you have exhaust to match.
You still have the same volume to fill with air/fuel mixture for each combustion unless you changed the bore and/or stroke. What rpm do you plan on running on a regular basis?
I vote for the 500cfm.

PACKERBACKER
07-18-2011, 04:43 PM
It is bored .030 over but not stroked. Future plans are to use the R3 headers and to convert the exhaust to 2-1/4". I also am planning to move the air cleaner next to the front of the radiator. The body is off so I will raise the front up 1" to allow the use of a set of high performance pulleys. The crank pulley does not clear the power steering ram without raising the engine some. The car also has an R3 carb box that was on it when I purchased it. No thoughts on what rpm to run it at.

PackardV8
07-18-2011, 05:27 PM
Just to let you know where I am coming from. My R2 Avanti has heads with R3 Valves, I had the heads opend up behind the valves, using the stiffer valve springs from Fairborn Studebaker, smoothed out and matched the ports and it has 1.75 ratio roller rockers from Ted Harbit and an aluminum intake manifold. It is pretty fast! That's an exceptionally nice build and you can be proud of it


No thoughts on what rpm to run it at. If you are still using the OEM R2 cam, the horsepower peak is 5,000 RPMs.

jack vines

Mike Van Veghten
07-18-2011, 05:36 PM
Packer -

Unless the person who did your heads has had a lot of Stude experience...there's a coupla things I'd bet he/she missed. At least you went in past just doing seat work, so at least you got that far. Many, if not most don't get that far.
There's two of us on the Stude Racing site that have spent about a year learning what it takes to get a Stude head to flow well. We also backed up each others work for verification on any given thing done.

BUT..be realistic. Is this a car that will be a normal driver...or an engine that will spend most of its time in the upper (above 4000rpm) rpm range.
If it will spend a good amount of time on some sort of race course...then go with the 600.
Otherwise........!

But...to be fair to the rest of us, you didn't mention any (many) details at the beginning of this thread, as notes in the above two or three posts....!

Mike

P.s. - I've got the best idea.
Buy both carburetors and you let "us" know which get's -
1. Better milage
2. Better driveability (better 60ft. times at the drag races)
3. Better E.T.'s (at the drag races)
4. Better MPH (at the drag races)

Stu Duglee
07-18-2011, 07:00 PM
I played musical carbs last summer when I installed a Offenhauser intake & a older Carter AFB on my non R series 289 in my 63 Hawk...The milage was great (20 mpg+) but it was old & ugly & if it sat for a day or two it was a bear to start but it would.So down to the FLAPS I went .I ended up buying a Edelbrock 600 & it was bolt on & go....but It was too much carb for my car,the gas milege was just as good but at full throttle it just didn't want to go...full speed ,it was holding back.This spring I bought a Edelbrock 500 Thunder series & what a nice difference,it goes like hell & gets good milage plus I like the AVS feature.Get a 500!

Reo28
07-18-2011, 11:32 PM
Thanks for all the posts guys. I see that this has created a bit of a stir of 500 vs 600CFM but all of the posts have been very useful. I am definitely going for the 500 on my standard engine, but it does look like the 600 may suit the higher powered and engineered Avanti engines. Each to their own, but I agree that this forum has members with years of experience and skinned knuckles - from engines, not fights!!
Mal

leyrret
07-20-2011, 07:17 PM
Here's my two cents. If you check the throttle and venturi size on a 500 and a 600, unless my memory fails they are the same on the primary side.
It would seem using vacuum operated secondaries there would be little if any difference between the two if correctly jetted and secondaries set to open at the right time. The difference would come to play at wide open throttle. The 400 afb has smaller primary and secondary and would likely give better low end and mileage. I have one I rebuild several years ago but have yet to try it. At present I'm still using a 390 Holley which also does well.
Terry

PackardV8
07-20-2011, 07:37 PM
If you check the throttle and venturi size on a 500 and a 600, unless my memory fails they are the same on the primary side.The throttle bores and the venturi diameter are the same. What makes it a 500 is a larger cluster in the center which restricts the flow. This gives a 16.6% higher velocity through the primaries for better throttle response at lower RPMs.


I'm still using a 390 Holley which also does well.Agree, a well-built Holley 390 CFM is the best carburetor I've ever used on smaller engines. Unfortunately, it doesn't bolt on to the Stude intake manifold. I have one which I modified the Holley base plate to the Stude bolt pattern. It looks a bit strange, but worked wonderfully well.

jack vines

leyrret
07-20-2011, 07:50 PM
I don't have my books here but it may be the the booster or secondary venturi in the primary is smaller. I believe the secondary throttle bore and venturi are larger on the 600. Too many numbers to remember.

Terry

Mike Van Veghten
07-20-2011, 09:18 PM
leyrret -

Reread jacks comment on the ventury sizes. The "plug" (or hugely thick booster ventury) in the primary side is what makes the 500 smaller. The venturies are actually the same.
My earlier comment should have been the total "square inches" of the ventury...not just the diameter on these two carburetors..
He is correct.

Mike