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Hi...

I already asked this question on the V8buick board but noone could answer so I#m going to try it here...

I checked the Id on my carb found out, that there isn't the original one installed...

I got a 67 Riviera (430) and the carb installed is a 7041540-so it should stand for

70-before 76

41- 1971

5-california emission

4-Buick

0-Automatic...right?

As I got another one in the trunk I'd like to know if it's probably the original one- but I can't identify that thing.

The numer is:7033744

So

70-before 76

33-??? no idea...the 67 had 27 or 37,right?

7-??

4-Buick

4-Automatic...also right?

I remember reading s.th about the fact that the 66+ 67 carbs had a round number at the back-just like mine ...but I can't find the webpage anymore...

Can anyone help?

Will there be a difference in performance if it should really be the original one?

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Here is the website:

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

The 7033744 number is a "casting" number, NOT a carburetor identification number; it is impossible to identify a Rochester carburetor from the castings numbers alone.

As to which one will work the best??? Hard to tell.

The original 1967 carbs (if you in fact have one), had a design problem, that if repaired when the carb is rebuild, gives no problems; BUT IF MUST BE ADDRESSED WHEN REBUILDING.

The later carb is designed for smog emissions, and if not modified, would not work as well as the original. However, the design of the 1971 is better; as the design problem of the 1967 was changed, and the float hanging mechanism was redesigned for better fuel control.

Jon.

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According to Cliff Ruggles book on Rochester Quadrajets, if the carb you're refering to is what you think is an original carb, there should be a circular metal tag on the body of the carb on the driver's side. Late 1968 and later carbs had the ID number roll-stamped into the body vertically in the driver's side rear corner.

Otherwise, here's how the ID numbers decode

702- 65-69 Federal

703- 65-69 CA and high altitude applications

704 - 70-75

1705 - 76-79

1708 - 80 - up

the next number is the last digit of the application year

the next number denotes "smog" - Federal = 1 or 2, or CA = 4 or 5.

the next number denotes application - 0,1,2 = Chevy; 3 = Cadillac; 4 = Buick; 5 = Oldsmobile; 6,7 = Pontiac; 8 = Checker or marine application.

the last digit tells the trans type - even numbers = automatic transmissions; odd numbers = standard transmissions.

Quadrajets are known as:

4M - manual choke

4MC - automatic choke - hot air

4MV - automatic choke - divorced

4ME - electric choke

There are more numbers for '75 and up that deal with Modified Q-jets, Altitude Q-jets, and Electric Q-jets.

The numbers you gave, 7033744, don't decode using these numbers. Look for the metal tag I referenced earlier.

You were correct on the first carb number you gave, 7041540, decodes as (even though we broke it down differently)

704 - 70-75

1-1971

5 - California application

4 - Buick

0 - automatic transmission

It should probably have a divorced choke that hooks to a bi-metal spring that's shrouded in the intake manifold.

Good luck on ID'ing the 703.... carb.

Ed

  • Thanks 1

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Ed - a comment on your post. The "coding" as you posted is correct maybe 95 percent of the time, but should be used AS A GUIDE ONLY!!! For accurate results, ALWAYS look up the number in a Rochester database.

No offense meant, simply trying to make these forums as accurate as possible.

I posted the above information in club magazine articles as early as 1975, with the 95 percent caviat. Somehow, over the years, the 95 percent caviat is often dropped.

Jon.

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Jon,

Thanks for the input. It's great that you're able to take time from your business to monitor these forums and give us the benefit of your years of experience. I know from having talked with you a couple of times about carburetion problems on a couple of my cars, that you've always been able to give me some good advice. I have a friend who built a 2x4 set up using an OEM manifold and some aftermarket carbs. I told him about the advice you gave on your website for running two four barrel carbs, he read it, followed it, and has been a happy camper ever since.

Thanks again,

Ed

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Ok...here are some pics of the carb...probably it will help to identify...

The number on the metalplate is:

BP(or RP) 29865

post-55049-143137991415_thumb.jpg

post-55049-143137991425_thumb.jpg

post-55049-143137991434_thumb.jpg

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Come on...If you all don't know it-noone knows...

I can't ask s.o. here in Germany about my Riviera, as the answer is always the same: "Dude...is that batman's car?"

:-)

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Your pictures are generic; they look like all other Quadrajets. You need to send pictures of ID numbers.

The basic differences are jetting, venturi area, and the way the choke works; otherwise they're all the same.

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Sorry...my good camera is broken...which numbers...?

There's only the 7033744 ( round )

and the BP(or RP) 29865 on the metal plate...

My choke-linkage comes from a bi-metal in the manifold...

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Good luck with that 703... carb. That number doesn't go along with what's available for decoding. As the owner of The Carburetor Shop said, you can only decode about 95% of the Rochester Q-jet carbs. Yours happens to fall into that other 5%. As Jon states in an earlier post, you're going to have to find access to a Rochester data base to ID this one.

If the number is stamped onto a round plate, at least you know it's a pre-1968 carb and the first Q-jets came out around 1965 - that narrows it down some but that's about as close as I can get. I have no idea what the 29665 number is unless it's an early Julian build date 298th day of '65.

I have a replacement carb for my 1966 Riv 425. The number on it doesn't decode, but I did find reference to it as an exact factory replacement for a '66 carb, but this carb was built a few years later than 1966.

There shouldn't be any appreciable difference in performance between this carb and the one that's on there now. They're both from the same era as ID'd by the round tag, so they're both 800 CFM carbs. 850's didn't appear until the early 70's, by then the tag had disappeared and all the carbs were roll stamped. If you need a rebuilding kit, I'd get one from Jon at www.thecarburetorshop.com he contributed a thread to this post earlier.

Keep searching and good luck.

Ed

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The correct carb for a 67 Riv is 7027240. If it is a CA car with AIR the number is 7027241. There is a 1/2" dia metal tag pressed into the left side of carb that has this number stamped on it. The tag will be red for the 7240 and yellow for the 7241. A couple differences between the two are the jets are.001 larger and the primary metering rods are .003 larger in the AIR carbs.

If you have any concerns with performance and your engine is stock, I'd replace it with an original rebuilt unit of the correct number. I found a rebuilt 7027240 on ebay last year and have seen others since for $179. The carb brought life to my car I never knew it had.

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I have a 67 Riv. I called up to order an accelerator pump. Gave her this # 702 7248. She told me it was a 67 Riv A/T.  Hello Jason, it's Cheech, the # you gave is for a GS.

Edited by Riv67 (see edit history)

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Here's a blurb from the ROA website about the '67 GS.  The same carb was used on ALL Riviera engines, GS and base, in '67.  The lady was correct.

 

Buick no longer used "Gran Sport" even in their brochures, it was just GS. As stated above, the interior was not part of the GS option. The new 430ci engine was introduced in 1967 and was standard on all Riviera models for the next three years. This was the only engine available and was used in the GS option as well. The engine code on the 430 was located on the right side of the engine below the spark plugs

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On 2/2/2019 at 11:04 PM, psychostang said:

Holy thread resurrection Batman!!  10-3/4 years!!  :)

 

That is (for me) the biggest advantage of the forum engines (especially over facebook) !

  • Like 1

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