Replacement carb for 1979 L48
Thread Starter
Advanced
Joined: May 2016
Posts: 95
Likes: 7
From: Tolland Massachusetts
Replacement carb for 1979 L48
I want to replace the carb on my 1979 C3. The mechanic I work with has strongly recommended that route as opposed to a rebuild kit. I would like to try and improve my performance on the 350 smallblock. I took the air cleaner off to see what the current carb is. It looks like the word "Rochester" is on the side. Some other letters look like "QUAR". Could someone please recommend a good replacement carb? The car was originally sold into California and I wonder if Chevy did something to the carb setup or use a different model carb then was on other C3s of that time period. I want to replace the carb so the car runs better. Thank you very much!
Philgran
Philgran '79 C3 Carb
Last edited by Philgran; Jan 11, 2018 at 05:23 PM. Reason: Want to add picture of current carb
Burning Brakes
Joined: Oct 2012
Posts: 1,152
Likes: 252
I'm not aware of any "new" Rochester Quadrajets. Rebuilt is your only option if you want to keep the carb factory. There are numerous places where you can buy an already rebuilt carb on exchange.
There are a couple of forum members that will rebuild for you also.
For "new" the Holley spreadbore series (4165/4175) are bolt on but they do need to be tuned to what your car wants.
There are a couple of forum members that will rebuild for you also.
For "new" the Holley spreadbore series (4165/4175) are bolt on but they do need to be tuned to what your car wants.
Le Mans Master
Joined: Oct 2007
Posts: 7,410
Likes: 949
From: Tennessee/Rhode Island
I have had a Holley 4175 650 CFM vacuum secondary Qjet replacement carb on my L-82 since 1985 and now still on the rebuilt 355 L-82 355 (carb rejetted) with 450+ Gross HP....great replacement carb for the Qjet.
Lars is also a great option for your OEM Qjet for him to rebuild it.
Lars is also a great option for your OEM Qjet for him to rebuild it.
Thread Starter
Advanced
Joined: May 2016
Posts: 95
Likes: 7
From: Tolland Massachusetts
Holley Spreadbore Series
I'm not aware of any "new" Rochester Quadrajets. Rebuilt is your only option if you want to keep the carb factory. There are numerous places where you can buy an already rebuilt carb on exchange.
There are a couple of forum members that will rebuild for you also.
For "new" the Holley spreadbore series (4165/4175) are bolt on but they do need to be tuned to what your car wants.
There are a couple of forum members that will rebuild for you also.
For "new" the Holley spreadbore series (4165/4175) are bolt on but they do need to be tuned to what your car wants.
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
Contact Lars v8fastcars@msn.com , he will make your carb work better than new and nothing on your engine will need to be modified like it would if you went to an aftermarket carb.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,112
From: Crossville TN
If that is the original Q-Jet which came from the factory on that engine (check the build date), you should just rebuild the carb with a kit you can purchase at NAPA or other decent car parts store. If that is a replacement carb which was purchased as REBUILT, you should send it to Lars Grimsrud (e-mail request to him at V8FastCars@msn.com) for having it properly rebuilt.
Swapping over what you now have (a stock induction system) to a square-bore carb would require a new intake manifold, etc. The carb you have is BETTER than any similar sized carb you can purchase; and the new carb purchase price is at least TWICE what it would cost to have Lars rebuild the one you have.
Swapping over what you now have (a stock induction system) to a square-bore carb would require a new intake manifold, etc. The carb you have is BETTER than any similar sized carb you can purchase; and the new carb purchase price is at least TWICE what it would cost to have Lars rebuild the one you have.
Last edited by 7T1vette; Jan 12, 2018 at 02:16 AM.
Le Mans Master
Joined: Oct 2007
Posts: 7,410
Likes: 949
From: Tennessee/Rhode Island
If that is the original Q-Jet which came from the factory on that engine (check the build date), you should just rebuild the carb with a kit you can purchase at NAPA or other decent car parts store. If that is a replacement carb which was purchased as REBUILT, you should send it to Lars Grimsrud (e-mail request to him at V8FastCars@msn.com) for having it properly rebuilt.
Swapping over what you now have (a stock induction system) to a square-bore carb would require a new intake manifold, etc. The carb you have is BETTER than any similar sized carb you can purchase; and the new carb purchase price is at least TWICE what it would cost to have Lars rebuild the one you have.
Swapping over what you now have (a stock induction system) to a square-bore carb would require a new intake manifold, etc. The carb you have is BETTER than any similar sized carb you can purchase; and the new carb purchase price is at least TWICE what it would cost to have Lars rebuild the one you have.
Last edited by jb78L-82; Jan 12, 2018 at 06:51 AM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
2027 Corvette vs The World: Every Model vs Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
Le Mans Master
Joined: Mar 2004
Posts: 7,423
Likes: 1,458
From: Little Rock AR
That Holley is easier to modify as compared to the Quadrajet but if you like to just drive a well running car the Quadrajet works best. I do run Holleys on other cars but the Quadrajet is the best carb for "set it up and forget about it" closed hood drivers. They work great when clean and adjusted right. California emissions calibration may be a bit too lean but nothing that could not be fixed when it is apart.
Send it to Lars is my advice. I carried mine to him years ago and it still works great.
Send it to Lars is my advice. I carried mine to him years ago and it still works great.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,112
From: Crossville TN
A "new" Holley will still cost twice as much as rebuilding the Q-Jet properly. The Holley will give no better performance and [most likely] less economy.
But the ability to swap over to that Holley [which is a good carb] is correct. If you go with the Holley, you will still have to figure out reconnecting all the emissions hoses, etc.
Your choice...
But the ability to swap over to that Holley [which is a good carb] is correct. If you go with the Holley, you will still have to figure out reconnecting all the emissions hoses, etc.
Your choice...
Last edited by 7T1vette; Jan 12, 2018 at 01:13 PM.
Race Director
Joined: Feb 2001
Posts: 10,992
Likes: 1,917
From: Grapevine Tx
2018 C3 of Year Finalist
2016 C3 of the Year Finalist
If that is the original Q-Jet which came from the factory on that engine (check the build date), you should just rebuild the carb with a kit you can purchase at NAPA or other decent car parts store. If that is a replacement carb which was purchased as REBUILT, you should send it to Lars Grimsrud (e-mail request to him at V8FastCars@msn.com) for having it properly rebuilt.
What's the difference?
Burning Brakes
Joined: Oct 2012
Posts: 1,152
Likes: 252
One company may consider "rebuilt" as cleaning it and throwing a new gasket/seal kit in it.
A good rebuild service will also measure for warp/leakages, validate it functions as should/make adjustments as needed, tune to your specific engine specs, etc. Probably 3-4 hours of billable work.
If someone offers a "rebuilt" carb for $100 + exchange then that means they spent about 20-30 minutes on it.
Sending a carb to LARS or anyone that is intimately knowledgeable of the operation and gotchas is money well spent. (disclosure: I do not know LARS as I do my own work but lots of positive threads here about his work)
Last edited by Dynra Rockets; Jan 12, 2018 at 02:34 PM.
Le Mans Master
Joined: Aug 2006
Posts: 7,411
Likes: 1,549
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
A commercial rebuilder may swap parts, jets sizes or rod sizes and the carb may never run correctly.
Lars was employed at GM in the q-Jet dept.
He will fix your carb correctly.
With a new carb, the fuel, accelerator cable and other lines may need to be modified.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,170
From: Hermosa
Contact Lars v8fastcars@msn.com , he will make your carb work better than new and nothing on your engine will need to be modified like it would if you went to an aftermarket carb.
Or if your a DIY guy get Cliff Ruggles' book buy the rebuild kit from him and do it yourself.
My Q-jet was a POS originally. After following Cliff's book and some of his performance tuning tips it now runs like fuel injection on a 440 HP 350.
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,027
Contact Lars v8fastcars@msn.com , he will make your carb work better than new and nothing on your engine will need to be modified like it would if you went to an aftermarket carb.
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
pretty crusty looking carb.
quite a bit of linkages and pull offs.
maybe warped.
I don't know your time requirement.
Can you remove and install a carb at home?
do you need the car running right away?
depending on the answers,
buy a Q-jet with they same numbers from a parts house.
all lines, fittings, hookups will be the same and an easy swap.
holley or some other carb will require time to adapt to the
lines and fittings. choke.
send yours to lars.and wait
buy a replacement and send your orig to lars.
Q-Jet is a good carb when rebuilt right.
quite a bit of linkages and pull offs.
maybe warped.
I don't know your time requirement.
Can you remove and install a carb at home?
do you need the car running right away?
depending on the answers,
buy a Q-jet with they same numbers from a parts house.
all lines, fittings, hookups will be the same and an easy swap.
holley or some other carb will require time to adapt to the
lines and fittings. choke.
send yours to lars.and wait
buy a replacement and send your orig to lars.
Q-Jet is a good carb when rebuilt right.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Burning Brakes
Joined: Oct 2015
Posts: 781
Likes: 113
I want to replace the carb on my 1979 C3. The mechanic I work with has strongly recommended that route as opposed to a rebuild kit. I would like to try and improve my performance on the 350 smallblock. I took the air cleaner off to see what the current carb is. It looks like the word "Rochester" is on the side. Some other letters look like "QUAR". Could someone please recommend a good replacement carb? The car was originally sold into California and I wonder if Chevy did something to the carb setup or use a different model carb then was on other C3s of that time period. I want to replace the carb so the car runs better. Thank you very much!
Philgran
Philgran '79 C3 Carb
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,027
Evil creatures. Lars won't poke them with a stick.
I have all The GM gizmos to do them correctly. (If that is a thing).
