Author Topic: Importance of a Correctly Dated Carburetor  (Read 9644 times)

chilipepper13

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Importance of a Correctly Dated Carburetor
« on: July 18, 2012, 02:36:45 PM »
Dear all

I recently acquired a nice 1969 SS/RS 350 convertible that is numbers matching and has been left pretty unmolested over the years. However a few sins were committed probably in the 80's  ;) namely the dash had been cut during the installation of a radio (NOS replacement has been ordered) the hood had been replaced (see my other post) and the carburetor had been replaced.

The carburetor's serial number 17059216 identifies it as a (carter manufactured) correct Rochester Quadrajet for an auto trans 350ci engine BUT with a production date of 1979. Since I'm pretty new to the car collectors scene I'd like to get your feedback if I should try to replace the carb with a correctly dated unit?

Thanks for your feedback,

Ed
Eddy C.

1969 SS/RS 350 Convertible

69Z28-RS

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Re: Importance of a Correctly Dated Carburetor
« Reply #1 on: July 18, 2012, 03:12:15 PM »
That's a great looking car, Eddy.

I think the correct carburetor for your car is pretty readily available (used); which you will need to get rebuilt.  There are a number of reliable re-builders for the Rochester Quad carbs (generally the throttle shaft has to be re-bushed)..  I'd get the carburetor asap.. as you never know how long old used parts are going to be available.

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68camaroz28

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Re: Importance of a Correctly Dated Carburetor
« Reply #2 on: July 18, 2012, 11:20:07 PM »
Check ebay as well. Nice looking ride Eddie!
Love the color combo.....
Chick
68 Z/28 NOR 01B Orig motor/trans/rear
69 Z/28 NOR 07A Orig Block & GM Cross-ram/carbs
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69pace

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Re: Importance of a Correctly Dated Carburetor
« Reply #3 on: July 19, 2012, 02:05:51 AM »
Nice ride - very clean, hows the engine bay looking?

If the carb installed was the "service replacement" Rochester Q-Jet (part number 7029209 which was also the part number in 69 for the Corvette 350/300 since GM always consolidated parts in the service life) - you could just leave it, but it looks like someone installed the 17059216 (= 1979 Rochester 4-brl , 305 & 350 ,Corvette, Camaro, Nova, Monte Carlo, EL Camino, Malibu and Passenger Auto trans with AC) as a substitute.  You may have to wait a while for your perfect carb to float by but they do all the time on eBay and other carb shops on line.  Rebuild is not so hard to do yourself.
1969 Z-11 350/300 with 4 Speed
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chilipepper13

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Re: Importance of a Correctly Dated Carburetor
« Reply #4 on: July 19, 2012, 10:59:21 AM »
Many thanks guys - love the ride too. You can imagine that in Euroland where most engines are 4cyl the rumble of a V8 get heads turning  ;D

69pace you nailed it, the 17059216 is exactly what's installed in my car. I did find an excellent remanufactured 69 Quadrajet with build date of 0069. I wonder though if this build date would make sense for an early 69 Camaro?  ???

My cars VIN indicates it was built in the Norwood plant in September 1968, so shouldn't the carb also have a September 1968 build date?


Thanks,

Ed
Eddy C.

1969 SS/RS 350 Convertible

69pace

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Re: Importance of a Correctly Dated Carburetor
« Reply #5 on: July 19, 2012, 09:29:18 PM »
0069 would the the sixth day of 1969 which is after your vehicle body date but that is only if you are really going for numbers matching/date matching. Ball park works for most folks too. There is a great posting here or on TC someplace (I can't get search to find anything today) that lists the common dates vs. build dates for all the major systems by production year and plant. The carb info was very useful because the poster mapped out the production bottlenecks and how Carter Rochester's filled the gap and kept production flowing. I think the carbs in early 69 were a month to a week before body build date but someone here in the know will post an update and maybe that thread with all the dates.
1969 Z-11 350/300 with 4 Speed
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chilipepper13

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Re: Importance of a Correctly Dated Carburetor
« Reply #6 on: July 20, 2012, 07:24:27 AM »
Many thanks!

I did some search on CRG myself but the only thing I found out is that carbs were usually produced before the VIN built date. The only thing puzzling me is that on the carburetor research topic here on CRG, 1968 Rochester Quadrajets were designed for the 350/295hp engine but I guess that the mid 1968 Quadrajet production actually should have changed to the 350/300hp engine, right?

Anyway, when I bought my car I never thought that I'd actually be buying a history project  ;) but it sure is fun chasing after all those details.
Eddy C.

1969 SS/RS 350 Convertible

69pace

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Re: Importance of a Correctly Dated Carburetor
« Reply #7 on: July 20, 2012, 11:27:47 AM »
I'm not sure if there was a jetting change between 295 to 300 HP 350 small blocks as I have never looked at the part numbers between the two. But if you find a ball park date jets can be changed easily. Production of parts was synchronized to model year so if there was a true difference in 295 vs 300 specs, a 300 would not have gotten a 295 carb, but if there is no difference the 295 part number inventory would be used up and replenished with the new part number carb.  So more research needs to be done to really understand.

As a note: The surviving "over the counter" and  Chevrolet service part number for my Rochester Q-jet carb for an L48 with manual transmission 7029203 was by the early 1980's listed in the parts catalog as the 1969 Corvette  Rochester Q-jet 7029207 version.  So if Chevrolet was rolling every carb toward the high end for parts consolidation you can assume you can use any 4mv base with correct pull-off and choke for your intake and transmission and rebuild it to the right specs.
1969 Z-11 350/300 with 4 Speed
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chilipepper13

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Re: Importance of a Correctly Dated Carburetor
« Reply #8 on: July 20, 2012, 10:48:51 PM »
Ok, so in addition to that early 1969 Quadrajet I came across a late May 1968 7028212 DH carburetor. Would that one be a better match for a September 1968 built 69 Camaro or should I stick with the Jan 1969 version?

Any thoughts are greatly appreciated  :)
Eddy C.

1969 SS/RS 350 Convertible

69pace

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Re: Importance of a Correctly Dated Carburetor
« Reply #9 on: July 20, 2012, 11:07:00 PM »
I would stay in the same production year if it was me.
1969 Z-11 350/300 with 4 Speed
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bc69

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Re: Importance of a Correctly Dated Carburetor
« Reply #10 on: May 29, 2017, 08:46:21 PM »
Does anybody have a list of the proper jets, needles for the different applications on the q-jet
Mainly the 69 L48 w/auto and air?
Body may be right but when these are rebuilt who knows what you get.
Brad
RSSS

TRLAND

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Re: Importance of a Correctly Dated Carburetor
« Reply #11 on: May 29, 2017, 10:06:57 PM »
Lars Grimsrud has a paper titled How to Tune a Q-Jet that covers that. Also, Cliff Ruggles book How to Rebuild and Modify Rochester Quadrajet Carburetors.

This is a 5 year old thread.  You may get more responses by starting a new one.
Mike in Northern Illinois
1967 RS 327