Carb
Thread Starter
Le Mans Master
Joined: Jul 2016
Posts: 8,433
Likes: 392
From: Oklahoma
Tech Contributor
Joined: Aug 1999
Posts: 14,366
Likes: 6,346
From: At my Bar drinking and wrenching in Lafayette Colorado
As noted in the e-mail I sent you earlier, you can use any 1968-1974 Chevy passenger car Q-Jet, but be aware that you will need to change your manifold choke coil if you have the correct 427 coil installed - it operates backwards from all other Q-Jet chokes.
Here are photos of a 1968 427 automatic Q-Jet, 7028216. This carb was produced later than the early ’68 manual carb shown previously, and deletes some of the 1967 features that were carried over to the early ’68 carbs:
Note that the choke blade screws have been moved farther apart. This choke blade configuration was retained for the duration of the Q-Jet production run:
These next 3 photos show the rear of the carb. Note that the Hot Idle Compensator has now been deleted – the casting is not drilled or tapped to accept it. Also note that these early Q-Jets have no provision for power brake vacuum in the carb base:
This carb has the correct steel inlet fitting:
On Big Block applications, the factory started cutting off the lower tip of the throttle lever to prevent the lever from touching the manifold. The cuts are always a little crude, and often look like a non-factory mod. In fact, they were done by the factory:
Unique 1968 428 Vette choke linkage with the “duckbill” counterweight. Same as the manual trans carb shown previously:
The complete “duckbill” choke system:
Another very unique feature on these 427 carbs are the 2 tubes in the airhorn rather than the usual 4. The outboard fuel discharge tubes for secondary tip-in enrichment are not used in these carbs:
There are no secondary fuel discharge holes drilled in the casting on these carbs – the entire fuel enrichment system is deleted:
Here are all the internal parts:
Lars
Here are photos of a 1968 427 automatic Q-Jet, 7028216. This carb was produced later than the early ’68 manual carb shown previously, and deletes some of the 1967 features that were carried over to the early ’68 carbs:
Note that the choke blade screws have been moved farther apart. This choke blade configuration was retained for the duration of the Q-Jet production run:
These next 3 photos show the rear of the carb. Note that the Hot Idle Compensator has now been deleted – the casting is not drilled or tapped to accept it. Also note that these early Q-Jets have no provision for power brake vacuum in the carb base:
This carb has the correct steel inlet fitting:
On Big Block applications, the factory started cutting off the lower tip of the throttle lever to prevent the lever from touching the manifold. The cuts are always a little crude, and often look like a non-factory mod. In fact, they were done by the factory:
Unique 1968 428 Vette choke linkage with the “duckbill” counterweight. Same as the manual trans carb shown previously:
The complete “duckbill” choke system:
Another very unique feature on these 427 carbs are the 2 tubes in the airhorn rather than the usual 4. The outboard fuel discharge tubes for secondary tip-in enrichment are not used in these carbs:
There are no secondary fuel discharge holes drilled in the casting on these carbs – the entire fuel enrichment system is deleted:
Here are all the internal parts:
Lars
Last edited by lars; Nov 27, 2016 at 02:07 PM.
Safety Car
Joined: Sep 2011
Posts: 4,102
Likes: 1,221
From: Madeira Beach, FL
2024 C8 of the Year Finalist - Unmodified
2024 C2 of the Year Finalist - Unmodified
2023 C2 of the Year Finalist - Unmodified
2020 C3 of the Year Finalist - Unmodified
Nicole,
I found my 1901 from another forum member.
You will find a working carb from this forum from Lars or another member.
These guys have allot of parts squirreled away.
Marshal
I found my 1901 from another forum member.
You will find a working carb from this forum from Lars or another member.
These guys have allot of parts squirreled away.
Marshal
Safety Car
Joined: Sep 2011
Posts: 4,102
Likes: 1,221
From: Madeira Beach, FL
2024 C8 of the Year Finalist - Unmodified
2024 C2 of the Year Finalist - Unmodified
2023 C2 of the Year Finalist - Unmodified
2020 C3 of the Year Finalist - Unmodified
Now that's what I call a tech session
Priceless.
Thanks,
Marshal
Priceless.
Thanks,
Marshal
As noted in the e-mail I sent you earlier, you can use any 1968-1974 Chevy passenger car Q-Jet, but be aware that you will need to change your manifold choke coil if you have the correct 427 coil installed - it operates backwards from all other Q-Jet chokes.
Here are photos of a 1968 427 automatic Q-Jet, 7028216. This carb was produced later than the early ’68 manual carb shown previously, and deletes some of the 1967 features that were carried over to the early ’68 carbs:
Note that the choke blade screws have been moved farther apart. This choke blade configuration was retained for the duration of the Q-Jet production run:
These next 3 photos show the rear of the carb. Note that the Hot Idle Compensator has now been deleted – the casting is not drilled or tapped to accept it. Also note that these early Q-Jets have no provision for power brake vacuum in the carb base:
This carb has the correct steel inlet fitting:
On Big Block applications, the factory started cutting off the lower tip of the throttle lever to prevent the lever from touching the manifold. The cuts are always a little crude, and often look like a non-factory mod. In fact, they were done by the factory:
Unique 1968 428 Vette choke linkage with the “duckbill” counterweight. Same as the manual trans carb shown previously:
The complete “duckbill” choke system:
Another very unique feature on these 427 carbs are the 2 tubes in the airhorn rather than the usual 4. The outboard fuel discharge tubes for secondary tip-in enrichment are not used in these carbs:
There are no secondary fuel discharge holes drilled in the casting on these carbs – the entire fuel enrichment system is deleted:
Here are all the internal parts:
Lars
Here are photos of a 1968 427 automatic Q-Jet, 7028216. This carb was produced later than the early ’68 manual carb shown previously, and deletes some of the 1967 features that were carried over to the early ’68 carbs:
Note that the choke blade screws have been moved farther apart. This choke blade configuration was retained for the duration of the Q-Jet production run:
These next 3 photos show the rear of the carb. Note that the Hot Idle Compensator has now been deleted – the casting is not drilled or tapped to accept it. Also note that these early Q-Jets have no provision for power brake vacuum in the carb base:
This carb has the correct steel inlet fitting:
On Big Block applications, the factory started cutting off the lower tip of the throttle lever to prevent the lever from touching the manifold. The cuts are always a little crude, and often look like a non-factory mod. In fact, they were done by the factory:
Unique 1968 428 Vette choke linkage with the “duckbill” counterweight. Same as the manual trans carb shown previously:
The complete “duckbill” choke system:
Another very unique feature on these 427 carbs are the 2 tubes in the airhorn rather than the usual 4. The outboard fuel discharge tubes for secondary tip-in enrichment are not used in these carbs:
There are no secondary fuel discharge holes drilled in the casting on these carbs – the entire fuel enrichment system is deleted:
Here are all the internal parts:
Lars
Drifting
Joined: Jul 2008
Posts: 1,873
Likes: 27
From: Sonora CA
Melting Slicks
Joined: Jul 2004
Posts: 2,131
Likes: 102
From: Toms River New Jersey
As noted in the e-mail I sent you earlier, you can use any 1968-1974 Chevy passenger car Q-Jet, but be aware that you will need to change your manifold choke coil if you have the correct 427 coil installed - it operates backwards from all other Q-Jet chokes.
Here are photos of a 1968 427 automatic Q-Jet, 7028216. This carb was produced later than the early ’68 manual carb shown previously, and deletes some of the 1967 features that were carried over to the early ’68 carbs:
Note that the choke blade screws have been moved farther apart. This choke blade configuration was retained for the duration of the Q-Jet production run:
These next 3 photos show the rear of the carb. Note that the Hot Idle Compensator has now been deleted – the casting is not drilled or tapped to accept it. Also note that these early Q-Jets have no provision for power brake vacuum in the carb base:
This carb has the correct steel inlet fitting:
On Big Block applications, the factory started cutting off the lower tip of the throttle lever to prevent the lever from touching the manifold. The cuts are always a little crude, and often look like a non-factory mod. In fact, they were done by the factory:
Unique 1968 428 Vette choke linkage with the “duckbill” counterweight. Same as the manual trans carb shown previously:
The complete “duckbill” choke system:
Another very unique feature on these 427 carbs are the 2 tubes in the airhorn rather than the usual 4. The outboard fuel discharge tubes for secondary tip-in enrichment are not used in these carbs:
There are no secondary fuel discharge holes drilled in the casting on these carbs – the entire fuel enrichment system is deleted:
Here are all the internal parts:
Lars
Here are photos of a 1968 427 automatic Q-Jet, 7028216. This carb was produced later than the early ’68 manual carb shown previously, and deletes some of the 1967 features that were carried over to the early ’68 carbs:
Note that the choke blade screws have been moved farther apart. This choke blade configuration was retained for the duration of the Q-Jet production run:
These next 3 photos show the rear of the carb. Note that the Hot Idle Compensator has now been deleted – the casting is not drilled or tapped to accept it. Also note that these early Q-Jets have no provision for power brake vacuum in the carb base:
This carb has the correct steel inlet fitting:
On Big Block applications, the factory started cutting off the lower tip of the throttle lever to prevent the lever from touching the manifold. The cuts are always a little crude, and often look like a non-factory mod. In fact, they were done by the factory:
Unique 1968 428 Vette choke linkage with the “duckbill” counterweight. Same as the manual trans carb shown previously:
The complete “duckbill” choke system:
Another very unique feature on these 427 carbs are the 2 tubes in the airhorn rather than the usual 4. The outboard fuel discharge tubes for secondary tip-in enrichment are not used in these carbs:
There are no secondary fuel discharge holes drilled in the casting on these carbs – the entire fuel enrichment system is deleted:
Here are all the internal parts:
Lars
Your detailed reply on this thread has helped me understand my problem much better. I have a 1968 427/390 4 speed car. The original carb 7028209 FG came with the car in a box from National carb rebuilders. It leaked all over and the fuel inlet had stripped threads.
National wasn't at all interested in the problem so based on earlier Forum advice I sent it to Cliff's and he repaired the leaking inlet and went through the internals to get it running right.
Now I'm struggling with the choke, can't get it to work at all. Once I read your input here and looked at the pictures I can see that I have the wrong choke mechanism on it. How hard is it to get the correct choke assembly you show in the pictures and do you sell them? I've attached a picture of what is on my card now. Also who sells the correct choke coil? Rich jcmsp062@aol.com
Tech Contributor
Joined: Aug 1999
Posts: 14,366
Likes: 6,346
From: At my Bar drinking and wrenching in Lafayette Colorado
Lars,
Your detailed reply on this thread has helped me understand my problem much better. I have a 1968 427/390 4 speed car. The original carb 7028209 FG came with the car in a box from National carb rebuilders. It leaked all over and the fuel inlet had stripped threads.
National wasn't at all interested in the problem so based on earlier Forum advice I sent it to Cliff's and he repaired the leaking inlet and went through the internals to get it running right.
Now I'm struggling with the choke, can't get it to work at all. Once I read your input here and looked at the pictures I can see that I have the wrong choke mechanism on it. How hard is it to get the correct choke assembly you show in the pictures and do you sell them? I've attached a picture of what is on my card now. Also who sells the correct choke coil? Rich jcmsp062@aol.com
Your detailed reply on this thread has helped me understand my problem much better. I have a 1968 427/390 4 speed car. The original carb 7028209 FG came with the car in a box from National carb rebuilders. It leaked all over and the fuel inlet had stripped threads.
National wasn't at all interested in the problem so based on earlier Forum advice I sent it to Cliff's and he repaired the leaking inlet and went through the internals to get it running right.
Now I'm struggling with the choke, can't get it to work at all. Once I read your input here and looked at the pictures I can see that I have the wrong choke mechanism on it. How hard is it to get the correct choke assembly you show in the pictures and do you sell them? I've attached a picture of what is on my card now. Also who sells the correct choke coil? Rich jcmsp062@aol.com
Classic Industries sells the coils, along with most of the Corvette restoration parts houses.
Lars
Last edited by lars; Nov 30, 2016 at 09:02 AM.
Melting Slicks
Joined: Jul 2004
Posts: 2,131
Likes: 102
From: Toms River New Jersey
I'm not aware of anyone selling the '68 duckbill choke systems. I come across used ones once in a rare while, and they sell immediately. Your best bet is to use the incorrect choke that's on your carb and use a 1970-1974 454 choke coil that has the correct windup rotation for the choke. You cannot use the 1968 choke coil with the choke system that's on your carb - it will cause the choke to be open when cold and to close as it gets hot.
Classic Industries sells the coils, along with most of the Corvette restoration parts houses.
Lars
Classic Industries sells the coils, along with most of the Corvette restoration parts houses.
Lars
jcmsp062@aol.com 732-244-6786
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Melting Slicks
Joined: Jul 2004
Posts: 2,131
Likes: 102
From: Toms River New Jersey
Thanks Lars, I'll get the 454 parts. Can you put me on a waiting list for the correct choke assembly. Just contact me next time you get one. Rich
jcmsp062@aol.com 732-244-6786
jcmsp062@aol.com 732-244-6786
Thanks to all the great information and pictures that Lars provided I managed to source a duck bill style choke to use on my 7028209 Quadrajet. Now it's not the correct Rochester part number but it looked so close I gave it a try and it fits and works well. It will do fine until I can find a RP 35853 choke assy. Thanks again Lars
Intermediate
Joined: Oct 2016
Posts: 30
Likes: 0
From: Sea Girt NJ
q-jet
Here are some photos of a 1968 427 Manual Tranny Q-Jet carb number 7028209:
Notice the choke blade screws are close together. This is indicative of an early ’68 carb. Very soon into the '68 production run, and all years after that, the choke screws are farther apart. 1966 - early 68 had the screws close together like this:
Notice the secondary airvalve rod correctly installed. The rod is missing on the OP's carb. The brass inlet fitting on this carb is not "correct": The correct fitting is steel:
Top view showing “doghouse” vent. This was used up through early 1970:
Note the hot idle vent cover in the back of the carb. This was used up through early 68 and discontinued very soon in the '68 model year:
Throttle lever is unique to 1968 - 1-year configuration:
Most unique part of the ’68 BB Vette carb is the choke system: The choke operates backwards from any other engine/carb, and has the choke attach rod forward of the pivot point. The BB carb only uses this “Duckbill” choke with a steel counterweight hanging off the rear - very rare, and difficult to "fake":
Lars
Notice the choke blade screws are close together. This is indicative of an early ’68 carb. Very soon into the '68 production run, and all years after that, the choke screws are farther apart. 1966 - early 68 had the screws close together like this:
Notice the secondary airvalve rod correctly installed. The rod is missing on the OP's carb. The brass inlet fitting on this carb is not "correct": The correct fitting is steel:
Top view showing “doghouse” vent. This was used up through early 1970:
Note the hot idle vent cover in the back of the carb. This was used up through early 68 and discontinued very soon in the '68 model year:
Throttle lever is unique to 1968 - 1-year configuration:
Most unique part of the ’68 BB Vette carb is the choke system: The choke operates backwards from any other engine/carb, and has the choke attach rod forward of the pivot point. The BB carb only uses this “Duckbill” choke with a steel counterweight hanging off the rear - very rare, and difficult to "fake":
Lars
Hello,
I was sent to you by ddawson about a Q-jet. a year ago I purchased a numbers matching 73 L48 except for the carb; which is a Holley 4360. The car runs fine except for the acc pump needs a rebuild. I'm think about putting a Q-jet back on, or rebuild the holley.
I had owned a new 75 and a few years later I rebuilt the Q-jet, so I'm not afraid to look for a decent Q-Jet rebuild.
Your thoughts.
-Ray