The Stovebolt Site Forums The Shop Area Engine Shop 283 Rochester 4 barrel 4gc

I want to change my old Rochester 4gc to a Eldelbrock 1406 carb
The auto choke doesn't work to well so my buddy and i figure why go through all the hassle to play around with the choke and see if we can fix it.
The cab is old so why not anew one has anyone ever used one of those Eldelbrock carbs and what do you think about them... It looks like you just take the old out and put the new in... This is the electric choke model... Any thoughts... thanks Peter

The Edelbrock carb is probably the most popular replacement out there. Every time you look under the hood at the shows & cruise nights most cars have one. They work real good out of the box & you can get a kit to taylor it to your engine. It is an easy swap but not as simple as you describe. You will have to make adjustments to the fuel line & throttle linkage. You will have to wire up the electric choke.

i have one on a 400 SBC and i like it

If the engine is basically stock, and you have any concerns about either fuel economy or low end driveability....stick with the original Rochester.

Depending on what year 283 intake manifold you are using, you may also need an adapter or change intakes.

Jon.

the 1406 boast better fuel economy and what do you mean by low end drive ability... Thanks Peter

I replaced a Q-jet with the 1406 last June.I had to run a switch controled wire for the choke, change the fuel supply a bit,and adapt the linkage.Not a big deal.It works fine out of the box.Looks cool too

I think you hit on the exact correct verb!

Long ago, in our local car club, a young man with a 396 Chevelle joined, and when asked about his engine, he boasted that he had fuel injection and (3) 4-barrels! :laughter:

Jon.

To give a somewhat more technical answer:

When Carter was still building the AFB carburetor, they built 505 different for different applications.

For basically stock Chevrolet engines, Carter recommended the following:

265 (warmed over) - 400 CFM (9400s/9410s)
283 (stock) - 400 CFM (9400s/9410s)
283 (high performance street or mild race) 500 CFM (4758s/4761s)
327 (stock) 500 CFM (9500s/9510s)
327 (high performance street or mild race) 625 CFM (4759s)
350 (stock) 600/625 CFM (I forget the number for the 600/9625s)
350 (very high performance street or mild race) 750 CFM (4760s/4762s)

All of the above are "square bore" carburetors. None will fit the factory 265 or pre-1961 283 intake manifolds without adapters. The 9400s/9410 will, I believe, fit the 1961-up 283 factory intake; no others will.

Carter had other recommendations if the manifold were switched to a "spread-bore" (ie Q-Jet style) manifold.

Installing too large a carburetor on any engine will kill low RPM air velocity, thus requiring an overrich mixture. If the engine has been modified with compression, cam, ignition; the larger carburetor will permit a higher RPM, thus more power at the higher RPM.

This article discusses several of the various CFM rating systems:

http://www.thecarburetorshop.com/Carbshop_carbsizesandCFM.htm

CFM requirements for a multi-cylinder four-stroke engine of at least 4 cylinders at a volumetric efficiency of 100 percent may be calculated at any RPM by the following:

CFM = (RPM times CID) / 3456.

I thought I had the explanation for this on our website, but it currently isn't. It will be!

Jon.

Jon Not to contradict your knowledge. I have heard and read that the conversions go quite smoothly with some adaption for linkage, fuel line and maybe a new flange. The results seem to be a great improvement over the 4gc. Saying that my main concern was getting away from the old type of auto choke and being able to install this myself. When I get in my car I want it to start not fiddle around with the choke etc. Peter

Peter - No offense taken, simply trying to answer your questions.

The electric choke can be useful for those living in very warm climates (needing very little choke), or those living further north with manual transmissions wishing to use A/M manifolds.

We get calls daily from those using electric chokes with older automatic transmissions that drive their vehicles in ambients of 65 degrees or less that have stall issues.

It is true that if you compare almost anything new to almost anything that needs attention that the new may function better.

However if you compare the new 600 CFM clone to the original Rochester WHICH ONE HAS RECONDITIONED, my guess as to the difference in performance would be:

Low end torque - Rochester +10~15 percent
Fuel economy, city driving - Rochester +25~40 percent
Fuel economy, highway - Rochester +10 percent
Hesitation from stop sign - Rochester - none
0-30 times - Rochester about 1 second quicker

I can think of no area of carburetion where the 600 CFM clone would be an improvement (or even as good) as a reconditioned original Rochester on a stock 283 engine, except possibly in initial convenience. If you really MUST do the clone thingy, then the 500 CFM clone would be MUCH less of a disadvantage, but all advantages other than initial convenience would still be the Rochester.

If you are capable of doing the necessary modifications (adapter, fuel line, linkage, air cleaner) to adapt the clone, you are also capable of rebuilding the original Rochester.

Obviously, the decision is entirely yours. Just wanted you to be aware of both pluses and minuses.

Jon.

Jon, you're arguing with another parts catalog expert- - - - -why bother? If JEGS or PAW says it will work, what's a professional fuel systems specialist who owns his own business supposed to do? Everybody knows those hundreds of special calibrations that GM and Carter made for OEM carburetors were really unnecessary, and three or four part numbers for replacement carbs make them all obsolete! (Where's the sarcasm icon?)

Good grief- - - -why do we bother offering advice that's ignored or ridiculed?
Jerry

Jon wasn't arguing with anyone, he was offering his opinion based on his knowledge. I have never seen him ignored or ridiculed. His posts are always humble and friendly.

This isn't a classroom where the teachers heavy handed 'advice' is doctrine, it's a forum where all folks offer their opinion.

Continually making people feel small and stupid is the "ignorance that can't be fixed!"

Stuart

Jerry - I wasn't trying to be argumentative, and I don't think Peter took it that way. As you suggest, some of the large aftermarket vendors sometimes oversell their wares. If alternatives are not presented, then anyone might believe that these advertisements are correct.

Peter - the article on selection is now on our website here:

http://www.thecarburetorshop.com/Carburetorsizeselection.htm

Since one of the examples used is a 283, you can see just how much overkill that a 600 CFM carb is for a 283.

Jon.

Thats what I Like about this site not to many take offense... just expressing their opinion...

I know you help on here to help others but you also have great business I think I talked to you on the Phone. Do you have recond 4gc carb for sale.Shall I call you and see what you would charge for a recond carb with a working choke. I prefer one already done..Your stats above look appealing comparing the two... Peter

By the way I would never try to offend anyone here...
I don't think the eldelbrock guy was trying to over sell me neither.. he was very helpful in fact he was underselling me if anything.. When you have a couple of regulars on here saying they are happy with the 1406 then they can't be that bad...

Now saying that I would go with Jon's advice and get a rebuilt 4gc if i know the thing will work. As Jon said I thought new would be better. The whole exercise here was to make sure when i go out into the damp cold air here in the Pacific Northwest the car will start and run thats all....

Peter - sold out of the carb you need, so the posts were strictly advice only, no axe grinding.

Go to your local auto parts store with the tag number on your carb, and acquire a rebuilding kit (or, if you would rather, call).

If you do not have a service manual for your car, get one! It will be handy for many other procedures. Part of the joy of owning an older vehicle is learning about it and solving issues. Read the section on rebuilding the Rochester before you disassemble the carb. If you have any questions, ask them here.

YOU CAN rebuild your carburetor!

Why spend the extra money to acquire another?

As far as the auto choke is concerned; call (normal telephone hours please) and I will be glad to explain its function, and what to do to make it work. The original choke will function far superior to an electric. Understanding is the key.

Try this one: http://www.thecarburetorshop.com/Automaticchokes.htm

Jon.

Thanks for all your help Jon If I do have problems I will call you... Thanks Peter

I thought I would report back to this forum on the great success with my Rochester 4gc carb. I took Jons sound advice and finally found someone in Eastern Canada who rebuilt the carb. The problem I had was all my contacts lead me nowhere. The places either didn't have parts or didn't want to fix it. Well Don form Toronto had all the parts and the know how to fix it for $200.00. I reinstalled it and after 3 cranks it started like it should... Thanks for all the advice I sure learned allot on this subject. If anybody needs the name of Don let me know..

Thanks again

Peter

Peter - glad that the gentleman in Toronto fixed the problem for you; and I am really glad you took the time to do a follow-up post.

Jon.