Neverending carb questions/dilemma - The 1947 - Present Chevrolet & GMC Truck Message Board Network

RapidRide2 · 10-09-2004, 11:17 PM

I am not trying to run this in the dirt. However I need some possibly unbiased (yeah right) opinions for my situations. 350 ci chevrolet in an 83' GMC. My engine will be putting out 285-295 h.p. yet with a somewhat steep 405-410 tq. at 2000 rpm's with a hydraulic roller. My goal is to get as good of a running street engine without losing economy or even possibly gaining some. Is it possible to get a holley 600cfm vac sec. to get as good as gas mileage as a Quadrajet??? I know almost nothing about a q-jet. From racing experience i know alot more about the holleys. Would the edelbrock carbs offer the smaller primaries of the q-jet??? On this engine i would give up 6-8 h.p.@6000 rpm's for 2-3 mpg's, however, i am really comfy with the holley design. Thanks to all who reply.

Toolboy23 · 10-09-2004, 11:44 PM

Not sure if they still make it, but ive seen holly spread bore carbs instead of the sqaure bore like the 600 if you fust prefer holly.

SanitysBane · 10-10-2004, 12:04 AM

a Q-jet will get better gas milllage than a holley, always.

RapidRide2 · 10-10-2004, 11:43 AM

even better than a holley spreadbore??? If so ,,, why?

SanitysBane · 10-10-2004, 03:01 PM

the holley's are made for racing aplications WOT, and the Q-jets were made for driving around, but the holley will help you out more on racing than the Q-jet will

plumbcut · 10-10-2004, 03:19 PM

everything has a learning curve. If you know holleys, you are inherently capable of knowing about q-jets too. you have to learn though. I say buy a couple junk q-jets and tear into them and rebuild one and see if you can get it running. they're great carbs. Dont listen to the people that call them quadrajunk, they're ignorant.

quadrajets were original equipment on zillions of different vehicles for many years. they're all about driveability and economy. Dont let those words fool you though- they also perform GREAT. The combination of throttle response, economy, tuneability, availability of parts, etc etc makes these carbs my #1 pick for ANYTHING that you plan on driving more than just on the weekend. They really are awesome. The old school holley and AFB style carbs are good too. Theyre tried and true but for the particular application of a TRUCK, the quadrajet is the way to go. If you wanna take the easy way out, throw a holley on there. yeah it'll work and if its setup right, it'll work great. Dont underestimate the quadrajet though. good luck

pc

jimfulco · 10-10-2004, 10:29 PM

The Q-jet not only has small front venturis, but each venturi has an extra booster in it, two boosters per side, one inside the other.

RapidRide2 · 10-11-2004, 06:56 PM

Where is the best place to get a good quadrajet. I really don't want a junkyard carb. Are the edelbrocks reman or are they new??? Good quality??? Or how about j.e.t. performance,,, How is their quality??? I haven't even purchased this 83' gmc w/ 305 yet. However i am pretty sure it has a q-jet on it already. However i am wanting to rid it of alot of emissions components and miles of vacuum lines from the carbs of that era. I may even get a spreadbore adapter and put on a new alum. intake. That will work with the 350 that will go in later.

10-10-2004, 12:04 AM	#3
SanitysBane Registered User Join Date: May 2004 Location: Lubbock, Texas Posts: 2,121	a Q-jet will get better gas milllage than a holley, always. __________________ '96 Nissan Pathfinder '02 Firebird Trans Am. '88 K5 Blazer

10-10-2004, 03:01 PM	#5
SanitysBane Registered User Join Date: May 2004 Location: Lubbock, Texas Posts: 2,121	the holley's are made for racing aplications WOT, and the Q-jets were made for driving around, but the holley will help you out more on racing than the Q-jet will __________________ '96 Nissan Pathfinder '02 Firebird Trans Am. '88 K5 Blazer

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10-09-2004, 11:17 PM	#1
RapidRide2 Registered User Join Date: May 2004 Location: Saint Louis Posts: 76	Neverending carb questions/dilemma I am not trying to run this in the dirt. However I need some possibly unbiased (yeah right) opinions for my situations. 350 ci chevrolet in an 83' GMC. My engine will be putting out 285-295 h.p. yet with a somewhat steep 405-410 tq. at 2000 rpm's with a hydraulic roller. My goal is to get as good of a running street engine without losing economy or even possibly gaining some. Is it possible to get a holley 600cfm vac sec. to get as good as gas mileage as a Quadrajet??? I know almost nothing about a q-jet. From racing experience i know alot more about the holleys. Would the edelbrock carbs offer the smaller primaries of the q-jet??? On this engine i would give up 6-8 h.p.@6000 rpm's for 2-3 mpg's, however, i am really comfy with the holley design. Thanks to all who reply.

10-09-2004, 11:44 PM	#2
Toolboy23 Registered User Join Date: Sep 2003 Posts: 30	Not sure if they still make it, but ive seen holly spread bore carbs instead of the sqaure bore like the 600 if you fust prefer holly.

10-10-2004, 11:43 AM	#4
RapidRide2 Registered User Join Date: May 2004 Location: Saint Louis Posts: 76	even better than a holley spreadbore??? If so ,,, why?

10-10-2004, 03:19 PM	#6
plumbcut california fill Join Date: Apr 2004 Location: Sunny So-Cal Posts: 694	everything has a learning curve. If you know holleys, you are inherently capable of knowing about q-jets too. you have to learn though. I say buy a couple junk q-jets and tear into them and rebuild one and see if you can get it running. they're great carbs. Dont listen to the people that call them quadrajunk, they're ignorant. quadrajets were original equipment on zillions of different vehicles for many years. they're all about driveability and economy. Dont let those words fool you though- they also perform GREAT. The combination of throttle response, economy, tuneability, availability of parts, etc etc makes these carbs my #1 pick for ANYTHING that you plan on driving more than just on the weekend. They really are awesome. The old school holley and AFB style carbs are good too. Theyre tried and true but for the particular application of a TRUCK, the quadrajet is the way to go. If you wanna take the easy way out, throw a holley on there. yeah it'll work and if its setup right, it'll work great. Dont underestimate the quadrajet though. good luck pc

10-10-2004, 10:29 PM	#7
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	The Q-jet not only has small front venturis, but each venturi has an extra booster in it, two boosters per side, one inside the other.

10-11-2004, 06:56 PM	#8
RapidRide2 Registered User Join Date: May 2004 Location: Saint Louis Posts: 76	Where is the best place to get a good quadrajet. I really don't want a junkyard carb. Are the edelbrocks reman or are they new??? Good quality??? Or how about j.e.t. performance,,, How is their quality??? I haven't even purchased this 83' gmc w/ 305 yet. However i am pretty sure it has a q-jet on it already. However i am wanting to rid it of alot of emissions components and miles of vacuum lines from the carbs of that era. I may even get a spreadbore adapter and put on a new alum. intake. That will work with the 350 that will go in later.



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