1980 Quadrajet - The 1947 - Present Chevrolet & GMC Truck Message Board Network

dan42 · 09-23-2007, 11:24 PM

I checked the numbers on the Quadrajet that is on the motor I'm gonna put in my '67, (a 350) and found that it was built in late '79, with California emissions, and was for a manual tranny (I'm gonna run a 4-speed). The P.O. said the motor ran great, but I never heard it. It was in a '79 Blazer, so it had to be smogged from time to time here in California. It is worth leaving on the motor and seeing how it runs, or swapping it out now? I'm not sure how much the smog stuff will actually affect the carb.

Thanks in advance.

dan42 · 09-24-2007, 09:59 AM

ttt

woodridge · 09-24-2007, 10:04 AM

I don't see any reason not to run it. You may need to re-jet it or change the power valve spring but it still just mixes air and fuel.

**StingRay** · 09-24-2007, 10:13 AM

The 79-80 q-jets were the best q-jet for all around performance and drivability. They are THE years to rebuild and use. They had them pretty well sorted out and then went on to those computer controlled q-jets and then efi. I personally sought out just that same carb to rebuild and use. A slightly better choice comes off of a 79-80 Z28 or vette.

**WorkinLonghorn** · 09-24-2007, 10:19 AM

Does it have idle mixture screws? That was one of the smog carb changes (we're talking California here);you couldn't adjust the idle unless you drilled out a plug or removed a limiter cap,but I'm not aware of any other negative aspect to these carbs.They were part of the CCS (Controlled Combustion System) which set a leaner mixture,higher engine operating temperature,and heated (100F) air intake.
I think I'd try it out and see how it works before deciding.

**StingRay** · 09-24-2007, 10:33 AM

I guess I should qualify that yes the idle air caps were removed and the jetting and rods/spring were optimized in my rebuild. It's the best core to build from though. The electric choke is a big plus for carb retrofitting too.

dan42 · 09-24-2007, 12:35 PM

Thanks for the good info, guys. I'll clean it up and see what it does.

**passthebuck** · 09-24-2007, 01:52 PM

StingRay is right - In terms of QJets, those are the best. I have a few that I've nabbed for future projects. A rebuild, new throttleshaft bushings & knock those plugs out & its a great carb.

*steveshow* · 09-24-2007, 02:40 PM

Ditto to PASSTHEBUCK. These carbs are hard to beat for a street truck, and can be made to run on the strip. THey offer better economy than Holley or other square flange carbs, and really go when those big secondaries open up. Keep a good fuel fliter on them and they will outlive you. There is a book on modifying these "Modifying Quadra jet carbs " or something to that effect, I have had it for yrs, forgot where I got it but I think they are on AMAZON.COM now. The book is worth its weght in gold.

forgeman · 09-25-2007, 08:11 PM

Rebuilt it! We have the technology we can make it better stronger faster. You will need the serial numbers off it or even better take the husk in with you to the auto store for a rebuild kit. (Get the correct one they can NOT be returned once opened.)

Give your self plenty of time and an organized workbench. The secret: it is easy if you take your time and have a "clean" area.

This is the rebuild of a 71 Rochester QuadraJet.

09-23-2007, 11:24 PM	#1
dan42 Registered User Join Date: Feb 2007 Location: Cali Central Coast Posts: 5,191	1980 Quadrajet I checked the numbers on the Quadrajet that is on the motor I'm gonna put in my '67, (a 350) and found that it was built in late '79, with California emissions, and was for a manual tranny (I'm gonna run a 4-speed). The P.O. said the motor ran great, but I never heard it. It was in a '79 Blazer, so it had to be smogged from time to time here in California. It is worth leaving on the motor and seeing how it runs, or swapping it out now? I'm not sure how much the smog stuff will actually affect the carb. Thanks in advance. Attached Images __________________ '67 SWB Fleetside ZZ4/350/Tremec 5-speed/4link/Scott's IFS - and fun as heck! SOLD Click here to support the board Philippians 4: 6-7

09-24-2007, 09:59 AM	#2
dan42 Registered User Join Date: Feb 2007 Location: Cali Central Coast Posts: 5,191	Re: 1980 Quadrajet ttt __________________ '67 SWB Fleetside ZZ4/350/Tremec 5-speed/4link/Scott's IFS - and fun as heck! SOLD Click here to support the board Philippians 4: 6-7

09-24-2007, 10:04 AM	#3
woodridge Senior Member Join Date: Feb 2005 Location: Maynardville, Tn Posts: 3,030	Re: 1980 Quadrajet I don't see any reason not to run it. You may need to re-jet it or change the power valve spring but it still just mixes air and fuel. __________________ SEMA Network- Protect our Hobby! 71 C30 in pieces, starting to come together. Click here for A Place For Tennessee Truck Enthusiest To Meet

09-24-2007, 10:13 AM	#4
StingRay Senior Member Join Date: Mar 2000 Location: Saskatoon,SK,Canada Posts: 2,476	Re: 1980 Quadrajet The 79-80 q-jets were the best q-jet for all around performance and drivability. They are THE years to rebuild and use. They had them pretty well sorted out and then went on to those computer controlled q-jets and then efi. I personally sought out just that same carb to rebuild and use. A slightly better choice comes off of a 79-80 Z28 or vette. __________________ Saskatoon, Saskatchewan Canada Last edited by StingRay; 09-24-2007 at 10:13 AM.

09-24-2007, 10:19 AM	#5
WorkinLonghorn Senior Member Join Date: Dec 2006 Location: Studio City, Calif. Posts: 2,861	Re: 1980 Quadrajet Does it have idle mixture screws? That was one of the smog carb changes (we're talking California here);you couldn't adjust the idle unless you drilled out a plug or removed a limiter cap,but I'm not aware of any other negative aspect to these carbs.They were part of the CCS (Controlled Combustion System) which set a leaner mixture,higher engine operating temperature,and heated (100F) air intake. I think I'd try it out and see how it works before deciding. __________________ '69 GMC C2500 Custom Camper, 8 1/2' bed, New GM 350, NP 435 Close Ratio 4spd. Trans., 3.73 Dana-60 open.Camper and Trailer wiring, PS, PB, AC, tach , three gas tanks, 2nd owner, Work-Truck supreme. Best $300 I ever spent. Last edited by WorkinLonghorn; 09-24-2007 at 10:21 AM.

09-24-2007, 10:33 AM	#6
StingRay Senior Member Join Date: Mar 2000 Location: Saskatoon,SK,Canada Posts: 2,476	Re: 1980 Quadrajet I guess I should qualify that yes the idle air caps were removed and the jetting and rods/spring were optimized in my rebuild. It's the best core to build from though. The electric choke is a big plus for carb retrofitting too. __________________ Saskatoon, Saskatchewan Canada

09-24-2007, 12:35 PM	#7
dan42 Registered User Join Date: Feb 2007 Location: Cali Central Coast Posts: 5,191	Re: 1980 Quadrajet Thanks for the good info, guys. I'll clean it up and see what it does. __________________ '67 SWB Fleetside ZZ4/350/Tremec 5-speed/4link/Scott's IFS - and fun as heck! SOLD Click here to support the board Philippians 4: 6-7

09-24-2007, 01:52 PM	#8
passthebuck Sisyphus was my mentor! Join Date: Sep 2002 Location: Carleton Place, Ontario CANADA Posts: 984	Re: 1980 Quadrajet StingRay is right - In terms of QJets, those are the best. I have a few that I've nabbed for future projects. A rebuild, new throttleshaft bushings & knock those plugs out & its a great carb. __________________ passthebuck #5642 -TWO 1967 GMC 910's. One with L6/3-on-the tree and the other with 355 w/435hp & a 700r4. -a 2013 Honda Civic as my "sensible" car

09-24-2007, 02:40 PM	#9
steveshow Account Suspended Join Date: Aug 2007 Location: Austin, Tx Posts: 81	Re: 1980 Quadrajet Ditto to PASSTHEBUCK. These carbs are hard to beat for a street truck, and can be made to run on the strip. THey offer better economy than Holley or other square flange carbs, and really go when those big secondaries open up. Keep a good fuel fliter on them and they will outlive you. There is a book on modifying these "Modifying Quadra jet carbs " or something to that effect, I have had it for yrs, forgot where I got it but I think they are on AMAZON.COM now. The book is worth its weght in gold.

09-25-2007, 08:11 PM	#10
forgeman Registered User Join Date: Sep 2007 Location: Columbia, MO Posts: 9	Re: 1980 Quadrajet Rebuilt it! We have the technology we can make it better stronger faster. You will need the serial numbers off it or even better take the husk in with you to the auto store for a rebuild kit. (Get the correct one they can NOT be returned once opened.) Give your self plenty of time and an organized workbench. The secret: it is easy if you take your time and have a "clean" area. This is the rebuild of a 71 Rochester QuadraJet. __________________ -- 72' Custom/20 In progress of overhaul: http://picasaweb.google.com/forgeman



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