350 4bbl carb replacement - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cheyenneman1 · 10-01-2009, 04:11 PM

I'm looking to replace my Rochester quadra-jet with a new carb. Looking for one that is going to require the least number of alteration, and I would like to keep my stock air cleaner.... any suggestions or ideas appreciated!

350 with 4bbl carb-stock everything (for now) 71 custom deluxe-10 2wd

mclairmo · 10-01-2009, 04:35 PM

Pony Carburetors, Inc. states that "The Quadrajet is a very wonderful carburetor. From the factory brand new, all one hundred and twenty million that were ever made had the following problems: They all had hesitations and flat spot on acceleration, a big bog on hard acceleration and hard starting when hot. Pony re-engineers the carburetors internally to take care of all these symptoms, and they run wonderfully when we get done. One note about an air valve secondary carburetor of which the Q- Jet is one, while we eliminate the bog on hard acceleration, the transfer of power when accelerating hard will still be a jerk when the secondaries open, not a smooth transition of power as a Holley Vacuum Secondary carburetor or as an Autolite 4100 performs." I use Holleys only and I love them, run awesome right out of the box. The new Summit carbs look good, too, they are based on the discontinued Holley 4010 which was a very nice carb which was, in turn, based on the Autolite 4100. I had an Autolite 2100 (2 barrel version of the 4100) on my 71 Mustang and it was great, never had a problem with it and I rebuilt it myself. I've also rebuilt Holleys and they are easy to rebuild and tune.

capev86 · 10-01-2009, 06:17 PM

never had any of those problems. any carb can issues when it gets old or neglected. everyone buys a holley because thats what's cool (like a farting bumblee muffler on a honda). the q-jet isn't really any more complicated than any other carb. whereas most carbs have equal sized primary and secondary bores, the q-jet uses small primaries for economy and huge secondaries for when you put your foot into it and some can flow up to 800cfm. they just had a segment on this on musclecar (poweblock tv) a couple weekends ago. there are a few modern miracle tweaks you can do to them to hop them up even more, but they were really awesome right out of the box. only thing better would be a properly tuned fuel injection setup because it can adjust to change in altitude and will beat any carb in fuel economy.

i have a 750 out of my dad's 84 burb that is going in my 72. i may rebuild it since it has been sitting several years and throw a better intake under it. edelbrock carries a nice intake for $150 through pep boys that is suposed to increase perfromance from idle to 5500rpm. i don't see myself redlining that long stroke 406 too often and it will be going in a 3/4 ton burb used primarily for cruising and trailer towing. i value torque and economy over max horsepower. i'm not sure if the manifold will take the quadrajet or just a holley or edelbrock special. the air cleaner box on off the 84 burb is huge. i might install the q-jet on the stock 307 before i do the engine swap (some time in the future) because the rochester 2 barrel on my truck is still not right even though i rebuilt it and i hope to hauling the the family camper (71 holiday) out to western mass next august for a big chevy/gmc truck (and vintage trailer) gathering.

Jim_PA · 10-01-2009, 06:31 PM

Stick with the qjet. You won't be sorry.

Jim_PA · 10-01-2009, 06:35 PM

Quote:

Originally Posted by mclairmo

One note about an air valve secondary carburetor of which the Q- Jet is one, while we eliminate the bog on hard acceleration, the transfer of power when accelerating hard will still be a jerk when the secondaries open, not a smooth transition of power as a Holley Vacuum Secondary carburetor or as an Autolite 4100 performs."

Then they have no clue what they are doing.

unclewatts · 10-02-2009, 04:26 AM

Quote:

Originally Posted by cheyenneman1

I'm looking to replace my Rochester quadra-jet with a new carb. Looking for one that is going to require the least number of alteration, and I would like to keep my stock air cleaner.... any suggestions or ideas appreciated!

350 with 4bbl carb-stock everything (for now) 71 custom deluxe-10 2wd

I'm with Jim_pa. Keep the Q-jet, but if you absolutely have to put on another carb, Edelbrock makes one called the "600CFM Performer" that they claim is a direct replacement for the Q-jet on our trucks. The fuel line goes in the same place, the air cleaner will fit and it's got all the ports that you'll need. If you want to see an ad for it, go to www.lmctruck.com page 58.

mclairmo · 10-02-2009, 01:48 PM

I would cruise all the carb posts here. Many love Edelbrocks, many hate them. Same for the Q-Jet.

10-01-2009, 04:11 PM	#1
cheyenneman1 Registered User Join Date: Mar 2009 Location: schenectady,new york Posts: 6	350 4bbl carb replacement I'm looking to replace my Rochester quadra-jet with a new carb. Looking for one that is going to require the least number of alteration, and I would like to keep my stock air cleaner.... any suggestions or ideas appreciated! 350 with 4bbl carb-stock everything (for now) 71 custom deluxe-10 2wd Last edited by cheyenneman1; 10-01-2009 at 04:13 PM.

10-01-2009, 04:35 PM	#2
mclairmo Registered User Join Date: Jan 2006 Location: Take Off Posts: 1,908	Re: 350 4bbl carb replacement Pony Carburetors, Inc. states that "The Quadrajet is a very wonderful carburetor. From the factory brand new, all one hundred and twenty million that were ever made had the following problems: They all had hesitations and flat spot on acceleration, a big bog on hard acceleration and hard starting when hot. Pony re-engineers the carburetors internally to take care of all these symptoms, and they run wonderfully when we get done. One note about an air valve secondary carburetor of which the Q- Jet is one, while we eliminate the bog on hard acceleration, the transfer of power when accelerating hard will still be a jerk when the secondaries open, not a smooth transition of power as a Holley Vacuum Secondary carburetor or as an Autolite 4100 performs." I use Holleys only and I love them, run awesome right out of the box. The new Summit carbs look good, too, they are based on the discontinued Holley 4010 which was a very nice carb which was, in turn, based on the Autolite 4100. I had an Autolite 2100 (2 barrel version of the 4100) on my 71 Mustang and it was great, never had a problem with it and I rebuilt it myself. I've also rebuilt Holleys and they are easy to rebuild and tune. Last edited by mclairmo; 10-01-2009 at 04:36 PM.

10-01-2009, 06:17 PM	#3
capev86 Registered User Join Date: May 2009 Location: Eliot, Maine Posts: 1,314	Re: 350 4bbl carb replacement never had any of those problems. any carb can issues when it gets old or neglected. everyone buys a holley because thats what's cool (like a farting bumblee muffler on a honda). the q-jet isn't really any more complicated than any other carb. whereas most carbs have equal sized primary and secondary bores, the q-jet uses small primaries for economy and huge secondaries for when you put your foot into it and some can flow up to 800cfm. they just had a segment on this on musclecar (poweblock tv) a couple weekends ago. there are a few modern miracle tweaks you can do to them to hop them up even more, but they were really awesome right out of the box. only thing better would be a properly tuned fuel injection setup because it can adjust to change in altitude and will beat any carb in fuel economy. i have a 750 out of my dad's 84 burb that is going in my 72. i may rebuild it since it has been sitting several years and throw a better intake under it. edelbrock carries a nice intake for $150 through pep boys that is suposed to increase perfromance from idle to 5500rpm. i don't see myself redlining that long stroke 406 too often and it will be going in a 3/4 ton burb used primarily for cruising and trailer towing. i value torque and economy over max horsepower. i'm not sure if the manifold will take the quadrajet or just a holley or edelbrock special. the air cleaner box on off the 84 burb is huge. i might install the q-jet on the stock 307 before i do the engine swap (some time in the future) because the rochester 2 barrel on my truck is still not right even though i rebuilt it and i hope to hauling the the family camper (71 holiday) out to western mass next august for a big chevy/gmc truck (and vintage trailer) gathering.

10-01-2009, 06:31 PM	#4
Jim_PA Registered User Join Date: May 2005 Location: PA Posts: 2,696	Re: 350 4bbl carb replacement Stick with the qjet. You won't be sorry.

10-02-2009, 01:48 PM	#7
mclairmo Registered User Join Date: Jan 2006 Location: Take Off Posts: 1,908	Re: 350 4bbl carb replacement I would cruise all the carb posts here. Many love Edelbrocks, many hate them. Same for the Q-Jet.



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