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-   -   Quadrajet Replacement (https://67-72chevytrucks.com/vboard/showthread.php?t=859624)

Bandit130 07-08-2025 01:35 PM

Quadrajet Replacement
 
Planning to replace the Carter Q-jet soon. Wanting to replace with new. Have not purchased new before, only had rebuild. Is there anything special needed to be done prior to install?

TIA

cadillac_al 07-08-2025 06:20 PM

Re: Quadrajet Replacement
 
Just save your old one because there is a good chance you will want to go back to it. All my old trucks still have the original carbs. I have a 74, two 76's, and a 77. They don't really wear out as far as I can tell. The throttle shafts may get a little loose but that minor vacuum leak doesn't seem to affect the way they run in my experience. I always change the throttle return spring to pull from the front to slow the throttle shaft wear.

As far as new, you are looking at an Edelbrock or Holly or a rebuilt Qjet which isn't really a new carb.

Ziegelsteinfaust 07-09-2025 03:54 AM

Re: Quadrajet Replacement
 
Get it rebuilt by a true professional. Such as Quadrajet power. Just to name one I get my parts from.

Bandit130 07-09-2025 11:45 AM

Re: Quadrajet Replacement
 
Had 2 rebuilds in 10 years. Last rebuild was in March by the same shop. This shop only works on carbs and throttle bodies. Been having fluctuating idle RPM and periodic dies possibly flooding on it's own.

The shop may not be rebuilding good enough not really sure.

geezer#99 07-09-2025 12:02 PM

Re: Quadrajet Replacement
 
Why do people always blame the carb?
Have you checked the distributor?
Could be weights and springs problem.
Have you checked initial timing?

Bandit130 07-09-2025 12:47 PM

Re: Quadrajet Replacement
 
Quote:

Originally Posted by geezer#99 (Post 9393287)
Why do people always blame the carb?
Have you checked the distributor?
Could be weights and springs problem.
Have you checked initial timing?

Yes. distributor checked out thoroughly. When it dies at stop sign or light, take of breather and can see gas on carb. After sitting for a few minutes, will start up and will be ok till the next time. Not a consistent occurrence.

Timing checked and adjusted as needed.

Loco83 07-09-2025 01:33 PM

Re: Quadrajet Replacement
 
I have 2 Rochester Qjets that have worked non stop for me, plan on keeping them forever. :lol:

Dead Parrot 07-09-2025 01:37 PM

Re: Quadrajet Replacement
 
Could be something as simple as the fuel filter going bad. Just takes a bit of rust or dying gas line or fuel filter bits to temporarily cause the needle/seat to let in too much gas.

It will be difficult to get a perfect match for your OEM carb even you buy a newly built Q-Jet. Likely your choice will be a generic tune for a stock 350 with options to buy jets and rods to tune to your application.

truckin 79 07-09-2025 07:12 PM

Re: Quadrajet Replacement
 
A quadrajet is easy enough to take off intake manifold and then remove top airhorn. I bet you just have some crap in fuel bowl or by the jets. Be carful with top airhorn gasket as it is easy to rip because primary metering rod hanger is in the way. There are plenty of videos online to guide you through this. Not a bad idea just to buy a rebuild kit just in case you do rip the top airhorn gasket. Also the float valve could be worn as well. I have gotten so good at takening off top airhorn I just do it on truck............I do not recommend.........only for the angry and pigheaded.

ron350 07-09-2025 07:56 PM

Re: Quadrajet Replacement
 
It is sad that so many people don't want to rebuild a Q-Jet because of the horror stories generated by people who did not purchase a Q-jet book.
I think the secondary metering rods and hanger messes them up.


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