Using rochester Quadrajet on mopar with GM/chevy linkage ?

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rustytoolss

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How much of a problem is to use a " GM/Chevy ) rochester quadrajet since it won't have the correct mopar linkage ?? you can fing them for less $$$ .
 
Compare the GM/Chevy linkage arm to any of the "universal" ones from Eddy/Holley- you likely can use one of their Mopar linkage adapters on the Q-Jet, might need a little work but should be close.
You will still need 4bbl. (or modded 2bbl.) throttle/kickdown brackets if you're converting from a 2bbl.
Well, and a spread bore manifold of course.
I do take issue with the statement " you can fing them for less $$$ ", though- Thermoquads in useable shape can generally be had pretty cheap. They may need to be gone through, but so will the Q-Jet.
 
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You should tell that to some of the GM stock eliminator guys that have BEAT Mopars AND Fords. They'd get a good laugh outta that one.
Exactly! An 87 Dodge Daytona running GT/ was sporting a 318 with oem cast iron intake topped with a Rochester and dialed in at 10.5 with 6000da...
 
How much of a problem is to use a " GM/Chevy ) rochester quadrajet since it won't have the correct mopar linkage ?? you can fing them for less $$$ .
I run the "GM" Rochester on LA with cast spreadbore intake in manual transmission applications all the time.

Cliff Ruggles Carburetors has some deep inventory if you’re looking for a specific throttle shaft. And he answers the telephone.!
 
Compare the GM/Chevy linkage arm to any of the "universal" ones from Eddy/Holley- you likely can use one of their Mopar linkage adapters on the Q-Jet, might need a little work but should be close.
You will still need 4bbl. (or modded 2bbl.) throttle/kickdown brackets if you're converting from a 2bbl.
Well, and a spread bore manifold of course.
I do take issue with the statement " you can fing them for less $$$ ", though- Thermoquads in useable shape can generally be had pretty cheap. They may need to be gone through, but so will the Q-Jet.
I guess I should have said that the GM version is more plentifull and can be bought for less money ( most of the time)
 
I agree with RRR, post #4. I have seen it with my own eyes. Damn good carb. There are people out there that can rebuild them, but it takes a Surgeon to make them work really good. I have a cast iron sb intake that I will use a q-jet on. I have several q-jets. 750 and 800 cfms.
 

I agree with RRR, post #4. I have seen it with my own eyes. Damn good carb. There are people out there that can rebuild them, but it takes a Surgeon to make them work really good. I have a cast iron sb intake that I will use a q-jet on. I have several q-jets. 750 and 800 cfms.
They quadrajets aren't very complex. I run a recalibrated 800 on my 318. The 800 is the carburetor you want to run because the primary venturi booster is far more sensitive.

This book, a wire drill set, with a pin vise and your in business. You need to pay attention to your idle hg before you build the carb. The recopies are in the book.

1766707942113.png
 
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They quadrajets aren't very complex. I run a recalibrated 800 on my 318. The 800 is the carburetor you want to run because the primary venturi booster is far more sensitive.

This book, a wire drill set, with a pin vise and your in business. You need to pay attention to your idle hg before you build the carb. The recopies are in the book.

View attachment 1716492608
Is the throttle linkage on the carburetor actually different from the GM carburetors? I didn't think it was. I thought Mopar simply made linkage that matched the carburetor. It's been so long since I've messed with one I cannot remember.
 
Is the throttle linkage on the carburetor actually different from the GM carburetors? I didn't think it was. I thought Mopar simply made linkage that matched the carburetor. It's been so long since I've messed with one I cannot remember.
I’d be happy to take a photo tomorrow.

I know when I dealt with Cliff I had a Buick carburetor that I was redoing and he sent me a GM throttle shaft. My recollection is GM is armed up and Buick and possibly Oldsmobile are arm down.

A lot of times I could find the 800s on a big block Pontiac tuna boat at pick n pull.

I don’t run automatics behind them, though.
 
There is a bigger qjet, but really hard to find. 850 cfm on a Pontiac 455 sw. I have a buddy that has 2 of them but won't come off either of them. I also have that book. There was a guy, Ray ?????, that ran a Chevelle conv in stock or s/s elim in the early 1970's. If i recall, you could send him your carb and 200.00 and he would "blueprint" and it was phenomenal.
 
There is a bigger qjet, but really hard to find. 850 cfm on a Pontiac 455 sw. I have a buddy that has 2 of them but won't come off either of them. I also have that book. There was a guy, Ray ?????, that ran a Chevelle conv in stock or s/s elim in the early 1970's. If i recall, you could send him your carb and 200.00 and he would "blueprint" and it was phenomenal.
Those SD cabs are worth 1000~
 
This post does not address the original query, but might provide some useful information for Chrysler application selection and to compare to the much broader GM Quadrajet applications.

The Quadrajet was used in 1985 - 1989 318 four barrel M-body cars and 1985 - 1988 360 four barrel truck applications. The car applications are all electronic feedback carburetors except the 1985 export versions including Canada. This 1985 model, Chrysler part number 4306411 and Rochester number 17085411, is the best of the Chrysler car versions to use and tune in other applications. The truck Quadrajet carburetors are not electronic feedback controlled. All of these Chrysler application Quadrajet carburetors had an integrated electric choke.

The following image shows a Chrysler small block Quadrajet installation with the single rod kickdown:
Screenshot 2025-12-25 8.20.25 PM.png


The following images show the throttle lever used on the Quadrajet in Chrysler applications:
Screenshot 2025-12-25 9.00.21 PM.png

Screenshot 2025-12-25 8.22.26 PM.png


The M-bodies used a three piece kickdown linkage setup, and the trucks used the single long rod with the Quadrajet. The following drawing shows the M-body kickdown linkage and throttle cable setup:
PXL_20251226_015317312.jpg



Following is a listing of Quadrajets used by Chrysler.

Rochester Quadrajet Listing

Carter ceased production of the Thermo-Quad after the 1984 model year. Chrysler switched to the Rochester Quadrajet M4ME and E4ME for 1985-1989.
  • M4ME = "Modified" (post 1974), 4 barrel Quadrajet, electric choke, non feedback.
  • E4ME = Electronic feedback, 4 barrel Quadrajet, electric choke.

NOTE: The identification number is stamped vertically on the left side near the secondary throttle lever.
Rochester Number
Application
Chrysler Number
Details
17085407
85-87 318
4306407
O2, E4ME
17085408
85-86 360 Truck
4306408
AT, Fed
17085409
85-86 360 Truck
4306409
AT, Fed, HA
17085411
85 318
4306411
Can, Exp
17085414
85-88 360 Truck
4306414
HD
17085415
85 360 Truck
4306415
HD, Fed, CA, Can
17085416
85-88 360 Truck
4306416
LD, Fed, CA, Can
17085417
85-86 360 Truck
4306417
MT, Fed
17085425
86 360 Truck
4306425
Fed
17085431
86 360 Truck
4306431
HD, CA, Can
17085432
85-88 360 Truck
4306432
HD
17085433
86-89 318
4306433
Fed, CA, Can, O2, E4ME
17085434
86 360 Truck
4306434
AT, Fed, CA, Can
17087175
88 360 Truck
4306419
AT, Fed
17087176
88 360 Truck
4306420
MT, Fed
17087177
88 360 Truck
4306424
AT, Fed, HA
17087245
88 360 Truck
4306437
Fed, CA, HD

Table Abbreviations:
  • AT = Automatic Transmission
  • MT = Manual Transmission ( No reference means both transmissions )
  • CA = California application; generic for CA, Sales code N95
  • Fed = Federal application ( No reference means both Federal and California.)
  • Can = Canada application. Typically, Canada used Federal carburetors except as noted.
  • Exp = Export
  • HD = Heavy Duty Cycle
  • HA = High Altitude
  • O2 = Feedback unit

 
This post does not address the original query, but might provide some useful information for Chrysler application selection and to compare to the much broader GM Quadrajet applications.

The Quadrajet was used in 1985 - 1989 318 four barrel M-body cars and 1985 - 1988 360 four barrel truck applications. The car applications are all electronic feedback carburetors except the 1985 export versions including Canada. This 1985 model, Chrysler part number 4306411 and Rochester number 17085411, is the best of the Chrysler car versions to use and tune in other applications. The truck Quadrajet carburetors are not electronic feedback controlled. All of these Chrysler application Quadrajet carburetors had an integrated electric choke.

The following image shows a Chrysler small block Quadrajet installation with the single rod kickdown:
View attachment 1716492621

The following images show the throttle lever used on the Quadrajet in Chrysler applications:
View attachment 1716492637
View attachment 1716492639

The M-bodies used a three piece kickdown linkage setup, and the trucks used the single long rod with the Quadrajet. The following drawing shows the M-body kickdown linkage and throttle cable setup:
View attachment 1716492638


Following is a listing of Quadrajets used by Chrysler.

Rochester Quadrajet Listing

Carter ceased production of the Thermo-Quad after the 1984 model year. Chrysler switched to the Rochester Quadrajet M4ME and E4ME for 1985-1989.
  • M4ME = "Modified" (post 1974), 4 barrel Quadrajet, electric choke, non feedback.
  • E4ME = Electronic feedback, 4 barrel Quadrajet, electric choke.

NOTE: The identification number is stamped vertically on the left side near the secondary throttle lever.
Rochester Number
Application
Chrysler Number
Details
17085407
85-87 318
4306407
O2, E4ME
17085408
85-86 360 Truck
4306408
AT, Fed
17085409
85-86 360 Truck
4306409
AT, Fed, HA
17085411
85 318
4306411
Can, Exp
17085414
85-88 360 Truck
4306414
HD
17085415
85 360 Truck
4306415
HD, Fed, CA, Can
17085416
85-88 360 Truck
4306416
LD, Fed, CA, Can
17085417
85-86 360 Truck
4306417
MT, Fed
17085425
86 360 Truck
4306425
Fed
17085431
86 360 Truck
4306431
HD, CA, Can
17085432
85-88 360 Truck
4306432
HD
17085433
86-89 318
4306433
Fed, CA, Can, O2, E4ME
17085434
86 360 Truck
4306434
AT, Fed, CA, Can
17087175
88 360 Truck
4306419
AT, Fed
17087176
88 360 Truck
4306420
MT, Fed
17087177
88 360 Truck
4306424
AT, Fed, HA
17087245
88 360 Truck
4306437
Fed, CA, HD

Table Abbreviations:
  • AT = Automatic Transmission
  • MT = Manual Transmission ( No reference means both transmissions )
  • CA = California application; generic for CA, Sales code N95
  • Fed = Federal application ( No reference means both Federal and California.)
  • Can = Canada application. Typically, Canada used Federal carburetors except as noted.
  • Exp = Export
  • HD = Heavy Duty Cycle
  • HA = High Altitude
  • O2 = Feedback unit

Excellent as usual! There clearly is a difference in the Chrysler throttle arm and GM arm. I know what the GM arm looks like and that ain't it. lol
 
I would use a 6000 series TQ. There is a huge variation in QJ designs, with changes and add ons over the years. Jim Hand is a Pontiac racer who ran his 455 powered 4000+lb LeMans wagon for years, HFT cam, home ported iron heads, QJ, 3.55 axle, T400 trans & Air cond. He got it down to mid-low11s. Somebody may know the exact number. He used a QJ, carefully massaged over the years.
He then tried an 800 cfm 9800 TQ, out of the box, no tuning. His comments are in his book, see below.
A LeMans that I tune weighs 3950 lb without driver, 455, T350, 3.36 diff, modified 6000 series 850 TQ has run 11.47 & 119 mph. I want to stress that the driver has had very limited drag strip racing, plus there was NO tuning at the strip such as changing the timing, jetting, tyre pressure etc. The numbers could be improved with more practice & on-track tuning.

img085.jpg
 
I would use a 6000 series TQ. There is a huge variation in QJ designs, with changes and add ons over the years. Jim Hand is a Pontiac racer who ran his 455 powered 4000+lb LeMans wagon for years, HFT cam, home ported iron heads, QJ, 3.55 axle, T400 trans & Air cond. He got it down to mid-low11s. Somebody may know the exact number. He used a QJ, carefully massaged over the years.
He then tried an 800 cfm 9800 TQ, out of the box, no tuning. His comments are in his book, see below.
A LeMans that I tune weighs 3950 lb without driver, 455, T350, 3.36 diff, modified 6000 series 850 TQ has run 11.47 & 119 mph. I want to stress that the driver has had very limited drag strip racing, plus there was NO tuning at the strip such as changing the timing, jetting, tyre pressure etc. The numbers could be improved with more practice & on-track tuning.

View attachment 1716492669
That Lemans wagon is super cool. Jim's son, Tom is a member here. I believe he still owns the wagon.
 
You should tell that to some of the GM stock eliminator guys that have BEAT Mopars AND Fords. They'd get a good laugh outta that one.
My carb-guy, raced NHRA super stock Chevys for decades. He's also an engine builder with a dyno. He would have given anything to have been able to run a Thermoquad on his Chevys.
On the same BB Chevy on his dyno, the Thermoquad he built for my car, made 20+ more HP, than one of his S/S Rochesters. It was down about 15 from a billet Holley. He builds a large percentage of the race Thermoquads for class cars, in the country. There's always a half-dozen TQ's in his shop, for his magic.

As for your Chevy racers beating Fords and mopars, it has more to do with the number of GM cars, rules, weight-breaks, and factoring....than anything else. I get a good laugh, out of silly stuff. Thank you.

Krusty carb.

Krusty Impastato Thermoquad.jpg
 
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