Quadrajet advise
Thread Starter
Cruising
Joined: Jan 2021
Posts: 14
Likes: 1
From: Logan Martin Lake, AL
Quadrajet advise
Hello all,
I've acquired another C3 (my third having long sold the first two) - a 1980. PO did not save anything and replaced the carburetor at some point with a square-bore Holley. The idle adjustment screws are close to ineffective and the accelerator pump actuator lever mechanisms lose contact regularly. I could get a big washer and rig the pump lever, but I'm leaning heavily toward going back to a Quardajet. All I'm finding locally are +81 electronic, or 305/350 thru 88 truck carbs. My question is, Are the thru 88 small block carbs without the electronic metering basically the same carb as the one that should be on my 80? There are four here locally to choose from that I can get for cheap to rebuild...
Kind regards.
I've acquired another C3 (my third having long sold the first two) - a 1980. PO did not save anything and replaced the carburetor at some point with a square-bore Holley. The idle adjustment screws are close to ineffective and the accelerator pump actuator lever mechanisms lose contact regularly. I could get a big washer and rig the pump lever, but I'm leaning heavily toward going back to a Quardajet. All I'm finding locally are +81 electronic, or 305/350 thru 88 truck carbs. My question is, Are the thru 88 small block carbs without the electronic metering basically the same carb as the one that should be on my 80? There are four here locally to choose from that I can get for cheap to rebuild...
Kind regards.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
If you want the carb to be compatible with all emissions systems and hoses on your '80, you need to find a 1979 or 1980 Chevy passenger car Q-Jet (and convert the '79 to electric choke). Don't get a truck carb (all 1981+ non-ECM Q-Jets are truck carbs). You can use any 1976 - 1980 passenger car Chevy carb, but most pre-'79 Q-Jets will not have the bowl vent provision for EVAP canister bowl purge.
Lars
Lars
Thread Starter
Cruising
Joined: Jan 2021
Posts: 14
Likes: 1
From: Logan Martin Lake, AL
Thank you Lars. I've been reading your posts and accolades. All of the emissions equipment was removed prior to my obtaining the car. Air pump, EGR, Charcoal canister, water temp switch vacuum, and most of the vacuum tubing... it's all gone and plugged. This is not a removal-from-road Sin in Alabama (black soot blowing exhaust is though).... The only vacuum accessories hooked to the Holley at this time are the distributor and PCV. Brake booster and trans mod are connected to manifold vacuum. I'll search for a unopened 76-80 though. Thank you!
Burning Brakes
Joined: Jan 2003
Posts: 961
Likes: 275
From: Frederick MD
Not sure if this matches your car/configuration but found this on ebay. https://www.ebay.com/itm/Chevrolet-C...sAAOSwMjVfb8XX Supposedly from my very brief research it fits 190 HP automatic cars but I'm sure somebody will have additional info to add.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
That's a commercially rebuilt carb with a horrible price. Good, rebuildable '76 - '80 Chevy passenger car Q-Jets currently sell for around $75 - $150.
Thread Starter
Cruising
Joined: Jan 2021
Posts: 14
Likes: 1
From: Logan Martin Lake, AL
Thank you kossuth, but I'm with Lars on this one. I'm looking for a good, unmolested core for a reasonable price... several on my FB Marketplace here between $40-$100. I have rebuilt a few Quadrajets in the past... and they've worked pretty well! lol Regardless, at this time I will likely look for someone with a good reputation to rebuild it for me.
Racer
Joined: Aug 2011
Posts: 493
Likes: 217
Make it easy, let Lars supply the core along with the rebuild. One of the critical parts of rebuilding these Q-Jets is getting the lead plugs sealed up, and covering with epoxy is not the answer. I'am sure Lars has this figured out.
Last edited by Vortecpro; Jan 11, 2021 at 08:45 AM.
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Melting Slicks
Joined: Oct 2000
Posts: 2,143
Likes: 195
From: Englewood FL
If you are looking for a good core, I am selling an original q jet for a 1980. It is for a 4 speed, so I believe that a linkage on the left side may need to be changed for the kick down on the auto transmission. It includes an AcDelco rebuild kit:
https://www.ebay.com/itm/293779514739
I purchased it, to have an extra numbers matching carb for my 1980, but sold the car.
https://www.ebay.com/itm/293779514739
I purchased it, to have an extra numbers matching carb for my 1980, but sold the car.
Last edited by mark79,80; Jan 11, 2021 at 10:33 AM.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
I don't supply cores, but I can assist you in finding one with some information I have available - e-mail me for the info. If your car is an automatic, you need a carb off of an automatic - not a 4-speed. The throttle shaft and lever will otherwise need to be swapped out with an auto shaft from a donor carb.
...And it's extremely rare for an M4M carb to have leaky well plugs. It was an occasional problem on early model 4MV models. I've never seen an M4M carb with leaky plugs in my 45 years in this business, and I test every one I build.
Lars
...And it's extremely rare for an M4M carb to have leaky well plugs. It was an occasional problem on early model 4MV models. I've never seen an M4M carb with leaky plugs in my 45 years in this business, and I test every one I build.
Lars