OEM carb swap 1983 / 1986

1983MonteLS

Not-quite-so-new-guy
Aug 1, 2022
24
3
I picked up a used carb from a guy from a 86 Regal with the computerized connections similar to my 83 quadrajet. There are a few things that are different which I expected, but the one that’s making it not work is the linkage for the accelerator. That whole plate is different. With these carbs in order to swap, what can I do to make it work with existing cables, etc (or am I unable)? I figured they are similar but unfamiliar with them. The 5204 is the number on the original and 6008 is the new one , thanks
 

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ck80

Comic Book Super Hero
Feb 18, 2014
4,187
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I picked up a used carb from a guy from a 86 Regal with the computerized connections similar to my 83 quadrajet. There are a few things that are different which I expected, but the one that’s making it not work is the linkage for the accelerator. That whole plate is different. With these carbs in order to swap, what can I do to make it work with existing cables, etc (or am I unable)? I figured they are similar but unfamiliar with them. The 5204 is the number on the original and 6008 is the new one , thanks
This is just guesswork from me, but, an 83 quadrajet would've been a factory design expecting a vacuum operated divorced solenoid on the fenderwell for cruise control

By 1986 all that stuff disappeared in favor of the rubber diaphragm with little chain. Etc.

In other words, a bunch of different stuff related to when a car got cruise and how it hooked up and was configured.

So maybe look there as a starting point?
 

spidereyes455

G-Body Guru
Mar 6, 2013
676
93
Northeastern PA
Try swapping the baseplate from your original carb to the replacement
 
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1983MonteLS

Not-quite-so-new-guy
Thread starter
Aug 1, 2022
24
3
Try swapping the baseplate from your original carb to the replacement
Thanks Ck80

Spide thanks for that advice, I did just that and everything went together nicely. I was running it and sounded good, some smoke from exhaust, and it started to rev high - looks like it has a rebuilt electric choke, but when I went to investigate it ran out of gas of course…
 

Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
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Galaxy far far away
An 86 Regal would have an Olds 307 V8. Qjets were setup very differently for each division. I assume you are trying to use this 86 Olds Qjet on a 83 Monte Carlo with a Chevy V8? If so then Just swapping the base plates will not make a Olds Qjet work correctly on a Chevy. You will need a CCC Qjet meant for a Chevy.
 

1983MonteLS

Not-quite-so-new-guy
Thread starter
Aug 1, 2022
24
3
I swapped it out fairly easily, and as mentioned I didn’t get a true feel for it all because I ran out of gas, what are the issues I’m going to run into leaving this carb hooked up?
 

Clone TIE Pilot

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Aug 14, 2011
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All sorts of weird diveabiity and tuning issues as Olds and Chevy use different calibrations within their respective Qjets. Different size jets, airbleeds, discharge ports, metering rods, etc. This is a big problem with reman Qjets is they often Frankenstein together mismatching parts from seversl cores leading to bizarre issues that most laymen can't figure out.

In fact Olds and Chevy CCC Qjets have so many differences they even have different carburetor model codes. Chevy is E4ME while Olds are E4MC. Fof a Chevy you need a E4ME. Even with E4MEs there are differences between the carbs for L69 and LG4 305s.
 

ck80

Comic Book Super Hero
Feb 18, 2014
4,187
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All sorts of weird diveabiity and tuning issues as Olds and Chevy use different calibrations within their respective Qjets. Different size jets, airbleeds, discharge ports, metering rods, etc. This is a big problem with reman Qjets is they often Frankenstein together mismatching parts from seversl cores leading to bizarre issues that most laymen can't figure out.

In fact Olds and Chevy CCC Qjets have so many differences they even have different carburetor model codes. Chevy is E4ME while Olds are E4MC. Fof a Chevy you need a E4ME. Even with E4MEs there are differences between the carbs for L69 and LG4 305s.
The e4mc vs e4me was only a designation between an electronic choke (e) vs automatic choke (c) on the carb. It wasn't about the other differences, such as angle the fuel feed went in, jets, or anything else. Just about choke type, which, you can swap over.

HurstOlds just did a nice write up and he adapted the relatively minor changes he made to use a Chevy main body on his 442 Olds carb rebuild. If you cared enough you could go the other way.

I'm no qjet carb guru. Somewhere novice to journeyman. But when it comes to those carbs, there's lots of info to unpack long term.

As far as reman units go... well, the BIGGEST problem is that they try to combine too many service numbers into one reman part number and ballpark settings. Yes, what you do with a buick 4.1 v6 qjet should be much different from a v8 almost 50% bigger.... except the reman house sells the same thing for em all under 1 number. That's the biggest problem, before you get into how they don't do a proper rebuild. The mix/match of components off different carbs into a Franken carb then comes in much further down.
 

Clone TIE Pilot

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Aug 14, 2011
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There are still a ton of differences between the two designations. Even the base plates between the two have big differences. The Chevy baseplates have a EGR vacuum port in the front passenger corner which Olds baseplates lack. Also the Chevy baseplate has newer tab style idle air bypass ports at the bottom of the primaries, under the throttle plates. While Olds baseplates lack idle air bypass ports under the throttle plates. Through the Olds do seem to have round ports just above the throttle plates, not sure if those are also idle air bypass ports or timed ports of some kind? Main point is that one has to really know what he or she is doing to use parts from different Qjet applications. I don'-t think the OP is knowledgeable enough to kitbash Qjets together from different models.

Qjets are not carbs to swap different parts around willy nilly. The external differences are only the tip of the iceberg. Another big difference betwern the two is that Olds carb use restrictors pressed into the air bleeds in the airhorn while Chevy airhorns lack air bleed restrictors. Moreover, the two have different fuel mixture dwell setting procedures. Olds you just adjust the IAB valve with the Thexton gage while Chevy requires final IAB valve setting with engine running and the use of an analog dwell meter. This suggests that Chevy uses a leaner idle mixture than Olds.

It boils down to how each GM division did things their own way. The CCC setup is very different betwern Buick 231s, Chevy 305s, and Olds 307s. You can't just cobble the different parts together like with each division's unique body and frame bracing setups.
 
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ck80

Comic Book Super Hero
Feb 18, 2014
4,187
113
There are still a ton of differences between the two designations. Even the base plates between the two have big differences. The Chevy baseplates have a EGR vacuum port in the front passenger corner which Olds baseplates lack. Also the Chevy baseplate has newer tab style idle air bypass ports at the bottom of the primaries, under the throttle plates. While Olds baseplates lack idle air bypass ports under the throttle plates. Through the Olds do seem to have round ports just above the throttle plates, not sure if those are also idle air bypass ports or timed ports of some kind? Main point is that one has to really know what he or she is doing to use parts from different Qjet applications. I don'-t think the OP is knowledgeable enough to kitbash Qjets together from different models.

Qjets are not carbs to swap different parts around willy nilly. The external differences are only the tip of the iceberg. Another big difference betwern the two is that Olds carb use restrictors pressed into the air bleeds in the airhorn while Chevy airhorns lack air bleed restrictors. Moreover, the two have different fuel mixture dwell setting procedures. Olds you just adjust the IAB valve with the Thexton gage while Chevy requires final IAB valve setting with engine running and the use of an analog dwell meter. This suggests that Chevy uses a leaner idle mixture than Olds.

It boils down to how each GM division did things their own way. The CCC setup is very different betwern Buick 231s, Chevy 305s, and Olds 307s. You can't just cobble the different parts together like with each division's unique body and frame bracing setups.
This all I agree with, EXCEPT what gm meant by their E4ME vs E4MC designation.

The last letter exclusively meant what choke it had. The fact the other differences existed had more to do with specialization to the engine, but we're NEVER the basis for using a 4th letter e vs c.

The nomenclature from Rochester was as follows:

4M is the universal Q-Jet model number.

Now, theres possible first letters... if nothing its an early 'original' style qjet, pre-emissions. Then you get the 'm' carbs, m4me/m4mc where the first m meant 'modified' in an era when most carbs running around werent changed for emissions yet so they wanted to differientiate and added a letter out front. Years later still you got the e4me/e4mc lines because, you guessed it, electronic control came around but manual carbs, mostly in the truck lines, were still non-computer.

The last letter is was and always will EXCLUSIVELY refer to the choke, regardless of any other differences present.

You could, in mid 70s being last i recall being in use, have a 'v' for divorced choke, a 'c' for the integrated/automatic choke on thebside of carb and run iff intake exhaust passage, usually via tubing, and the 'e' for a full on electric choke.

And, when it comes to lettering which is all i keep getting at, that's it. Buying an 'e4me' doesn't guarantee it is a 'Chevy style qjet' at all, and, buying a 'Chevy style qjet' doesn't mean it's an 'e4me'

Also, for what it's worth, buying an e4mc doesn't mean it is an Oldsmobile carb either. Here's just one top of the head example. The e4mc was used on the Buick 350. Living out its last years in the riviera and big cars. Certainly not an Olds engine, and certainly not chock full of Olds uniquely tailored specs.
 
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