Carb Question - 2BBl or 4BBl - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Ironhorse** · 08-01-2007, 10:07 PM

I have the chance to pick up a Q-jet carb for little of nothing. Elec. choke and needs re-build. My truck currently has a Rochester 2BBl with stock cast iron intake. Truck is a stock 350 4x4 with 4 speed and stump puller gearing. Needs all the help in can get mileage wise. TBI is not an option so question is:

Considering all the angles, such as miles per gallon, pulling power, driveability, ease of maintenace, etc: Which would you use, the Q-jet or the current 2 bbl carb. Also have a early 80's Camaro Z-28 GM aluminum Q-jet intake so the intake question is already taken care of.

On a good day the truck gets around 11.5 mpg. at about steady 55 mph. Would I see much improvement with the 4BBl Q-jet? Have had several guys at work tell me it will do better than the 2BBl if I leave the foot out of the back two butterflies.

scooter122983 · 08-01-2007, 10:13 PM

For a off road truck get rid of the quadrapuke and throw a off road avenger. I have a street avenger and the tunability is easy as hell. Vacume secondary with the quick change spring already installed two screws for idle mix and the choke is easy to adjust as well. It also should come with clear sight plugs for the bowls. It took me about 2 hours to get everything working the way I wanted it. I understand that I have the street avenger, but the Off Road avenger is the same carb with a few changes like the vent tube.

Robert1970C20rstbukt · 08-01-2007, 10:23 PM

If you have the intake and can get the carb go with the Qjet. You will get better mileage with the Qjet if you don't hot rod it. The primaries on a Qjet are smaller than the ones on the 2bbl, that's why it get's better mileage. That's what I did when we put the 307 in my truck. I also wanted the 4bbl for more power when I needed it towing or hauling.

Jim_PA · 08-01-2007, 10:26 PM

Those that know Qjets will tell you they are better than any aftermarket carb for street and off-road. The others just don't know what they are doing

**Ironhorse** · 08-02-2007, 05:01 AM

Don't really "use" the truck for off-roading. It's not a show truck but have to much invested to take the truck "muddin". Mostly just use the truck when I need a truck for hauling and a get around vehicle. Just needs help in the mpg department. Thanks for the replies, keep'em coming.

**special-K** · 08-02-2007, 05:37 AM

That guy`s been learnin`from offroad magazines.The quadrajet is a great carb and,as said,will give better economy than the 2bbl.

68gmsee · 08-02-2007, 09:25 AM

I think "scooter" assumed you were doing offroad driving and was referring to the simplicity of the offroad avenger in comparison to the quadrajet. Quadarajets are difficult to mess with if you're not familiar with them. I'd let a shop clean and overhaul.

That being said, if you already have the carb and are famiiar with overhauling and cleaning them, go for it. Once they're in good working condition they're hard to beat. I've had one for many years and still working good.

They are more economical than the 2 barrel. Not much, but these days everything counts.

**VetteVet** · 08-02-2007, 11:09 AM

If you do go with the Q-jet and you want to rebuild it, these websites will be a lot of help.
http://www.4wheelnoffroad.com/qjet.html
http://www.florida4x4.com/tech/quadrajet/

Overkill67 · 08-02-2007, 01:23 PM

definatly better off with the 4bbl over the 2bbl for mpg. Also when you get behind that one guy who drive across teh country at 30mph in a 55 zone, nothing beats the sound of the vacum when the secondaries kick in lol

gkolmatycki · 08-02-2007, 02:45 PM

Swap the 4BBL quadrajet & the aluminum Z-28 intake for that 2BBL. I was wondering the same thing a while back on my 327. Made the swap & never been happier. A few more MPG if I stay out of the secondaries & a lot more power when I open it up at WOT.

BCOWANWHEELS · 08-02-2007, 03:13 PM

do you know what a real z28 intake is worth ?

Jim_PA · 08-02-2007, 04:01 PM

Quote:

Originally Posted by BCOWANWHEELS

do you know what a real z28 intake is worth ?

Scrap weight from an early 80's Z.

gkolmatycki · 08-02-2007, 04:06 PM

True. I would love to have an original high rise '69 Z28 intake.

GMC AMI · 08-02-2007, 04:19 PM

Quote:

Originally Posted by gkolmatycki

True. I would love to have an original high rise '69 Z28 intake.

How about an original 72 Corvette high rise one? The highest one I ever ran across. Snow stamped and all in perfect condition.

**Ironhorse** · 08-03-2007, 09:59 PM

Thanks for all the replies to the carb question. Since the truck is not really a mudder or off road vehicle I think the Q-jet should do just fine. I also wish the intake was from a 1st Gen. Camaro Z-28. Wouldn't be wasting it by putting it on the truck, for sure.

08-01-2007, 10:07 PM	#1
Ironhorse Senior Member Join Date: Jul 2001 Location: Wellington, Ks Posts: 10,294	Carb Question - 2BBl or 4BBl I have the chance to pick up a Q-jet carb for little of nothing. Elec. choke and needs re-build. My truck currently has a Rochester 2BBl with stock cast iron intake. Truck is a stock 350 4x4 with 4 speed and stump puller gearing. Needs all the help in can get mileage wise. TBI is not an option so question is: Considering all the angles, such as miles per gallon, pulling power, driveability, ease of maintenace, etc: Which would you use, the Q-jet or the current 2 bbl carb. Also have a early 80's Camaro Z-28 GM aluminum Q-jet intake so the intake question is already taken care of. On a good day the truck gets around 11.5 mpg. at about steady 55 mph. Would I see much improvement with the 4BBl Q-jet? Have had several guys at work tell me it will do better than the 2BBl if I leave the foot out of the back two butterflies. __________________ 1971 Chevy 1/2T 4x4 LWB 350 V-8 Was sm465-now 350TH/np205 Tilt, Tach, Towhooks Original Truck AM/FM Wellington, Ks

08-01-2007, 10:13 PM	#2
scooter122983 The Man The Myth The Mystery Join Date: Jul 2007 Location: Des Moines, IA Posts: 114	Re: Carb Question - 2BBl or 4BBl For a off road truck get rid of the quadrapuke and throw a off road avenger. I have a street avenger and the tunability is easy as hell. Vacume secondary with the quick change spring already installed two screws for idle mix and the choke is easy to adjust as well. It also should come with clear sight plugs for the bowls. It took me about 2 hours to get everything working the way I wanted it. I understand that I have the street avenger, but the Off Road avenger is the same carb with a few changes like the vent tube. Last edited by scooter122983; 08-01-2007 at 10:15 PM.

08-01-2007, 10:23 PM	#3
Robert1970C20rstbukt Registered User Join Date: Jun 2004 Location: Beeville, Texas Posts: 1,943	Re: Carb Question - 2BBl or 4BBl If you have the intake and can get the carb go with the Qjet. You will get better mileage with the Qjet if you don't hot rod it. The primaries on a Qjet are smaller than the ones on the 2bbl, that's why it get's better mileage. That's what I did when we put the 307 in my truck. I also wanted the 4bbl for more power when I needed it towing or hauling. __________________ RJD 1984 Chevrolet C30 welding truck 454/SM465 1977 GMC C15 pickup 350/TH350 1970 Chevrolet C20 pickup 350/TH400 1970 Chevrolet K20 Suburban 454/TH350 1969 GMC 8500 478M V6/5 spd winch truck

08-01-2007, 10:26 PM	#4
Jim_PA Registered User Join Date: May 2005 Location: PA Posts: 2,696	Re: Carb Question - 2BBl or 4BBl Those that know Qjets will tell you they are better than any aftermarket carb for street and off-road. The others just don't know what they are doing

08-02-2007, 05:01 AM	#5
Ironhorse Senior Member Join Date: Jul 2001 Location: Wellington, Ks Posts: 10,294	Re: Carb Question - 2BBl or 4BBl Don't really "use" the truck for off-roading. It's not a show truck but have to much invested to take the truck "muddin". Mostly just use the truck when I need a truck for hauling and a get around vehicle. Just needs help in the mpg department. Thanks for the replies, keep'em coming. __________________ 1971 Chevy 1/2T 4x4 LWB 350 V-8 Was sm465-now 350TH/np205 Tilt, Tach, Towhooks Original Truck AM/FM Wellington, Ks

08-02-2007, 05:37 AM	#6
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Carb Question - 2BBl or 4BBl That guy`s been learnin`from offroad magazines.The quadrajet is a great carb and,as said,will give better economy than the 2bbl. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

08-02-2007, 09:25 AM	#7
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: Carb Question - 2BBl or 4BBl I think "scooter" assumed you were doing offroad driving and was referring to the simplicity of the offroad avenger in comparison to the quadrajet. Quadarajets are difficult to mess with if you're not familiar with them. I'd let a shop clean and overhaul. That being said, if you already have the carb and are famiiar with overhauling and cleaning them, go for it. Once they're in good working condition they're hard to beat. I've had one for many years and still working good. They are more economical than the 2 barrel. Not much, but these days everything counts.

08-02-2007, 11:09 AM	#8
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,719	Re: Carb Question - 2BBl or 4BBl If you do go with the Q-jet and you want to rebuild it, these websites will be a lot of help. http://www.4wheelnoffroad.com/qjet.html http://www.florida4x4.com/tech/quadrajet/ __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

08-02-2007, 01:23 PM	#9
Overkill67 Registered User Join Date: Apr 2007 Location: Roselawn, Indiana Posts: 60	Re: Carb Question - 2BBl or 4BBl definatly better off with the 4bbl over the 2bbl for mpg. Also when you get behind that one guy who drive across teh country at 30mph in a 55 zone, nothing beats the sound of the vacum when the secondaries kick in lol

08-02-2007, 02:45 PM	#10
gkolmatycki Love that '69 Join Date: Oct 2005 Location: Sherwood Park, Alberta, Canada Posts: 109	Re: Carb Question - 2BBl or 4BBl Swap the 4BBL quadrajet & the aluminum Z-28 intake for that 2BBL. I was wondering the same thing a while back on my 327. Made the swap & never been happier. A few more MPG if I stay out of the secondaries & a lot more power when I open it up at WOT. __________________ I AM CANADIAN & PROUD OF IT!!! 1969 Chevy C10, SBC V8, TH-350 Transmission, Metallic Blue, B&M Megashifter, GT Grant Steering Wheel, 2.25" True Dual Magnaflow Exhaust System w/ SS Magnaflow Embossed Tips, 700W Rockford Fosgate Stereo System, Lowered 1" Front & Stock Rear, 4.56 Rear with Positraction, 15" Chrome Rims w/ Chevy Center Caps & Michelin Tires, 4.5" K&N Air Filter, Edelbrock 'Elite' Engine Accessories, Chrome Powdercoated Engine Parts 2001 Cavalier Z24, 2.4L DOHC, Silver, Spoiler, AEM Intake, 2.25" Magnaflow Exhaust System, Clear Euro Tails, Tinted Windows, 400W Clarion Stereo System

08-02-2007, 03:13 PM	#11
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: Carb Question - 2BBl or 4BBl do you know what a real z28 intake is worth ? __________________ I BELIEVE IN JOHN 3:16

08-02-2007, 04:06 PM	#13
gkolmatycki Love that '69 Join Date: Oct 2005 Location: Sherwood Park, Alberta, Canada Posts: 109	Re: Carb Question - 2BBl or 4BBl True. I would love to have an original high rise '69 Z28 intake. __________________ I AM CANADIAN & PROUD OF IT!!! 1969 Chevy C10, SBC V8, TH-350 Transmission, Metallic Blue, B&M Megashifter, GT Grant Steering Wheel, 2.25" True Dual Magnaflow Exhaust System w/ SS Magnaflow Embossed Tips, 700W Rockford Fosgate Stereo System, Lowered 1" Front & Stock Rear, 4.56 Rear with Positraction, 15" Chrome Rims w/ Chevy Center Caps & Michelin Tires, 4.5" K&N Air Filter, Edelbrock 'Elite' Engine Accessories, Chrome Powdercoated Engine Parts 2001 Cavalier Z24, 2.4L DOHC, Silver, Spoiler, AEM Intake, 2.25" Magnaflow Exhaust System, Clear Euro Tails, Tinted Windows, 400W Clarion Stereo System

08-03-2007, 09:59 PM	#15
Ironhorse Senior Member Join Date: Jul 2001 Location: Wellington, Ks Posts: 10,294	Re: Carb Question - 2BBl or 4BBl Thanks for all the replies to the carb question. Since the truck is not really a mudder or off road vehicle I think the Q-jet should do just fine. I also wish the intake was from a 1st Gen. Camaro Z-28. Wouldn't be wasting it by putting it on the truck, for sure. __________________ 1971 Chevy 1/2T 4x4 LWB 350 V-8 Was sm465-now 350TH/np205 Tilt, Tach, Towhooks Original Truck AM/FM Wellington, Ks



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.