I had Lars rebuild my QJ and I wouldn’t consider anything else. Starts great cold and warm , very good throttle response, and made very good HP on the dyno.

Just don’t expect to send a “mix matched “ Q core to a rebuilder, they must have the correct parts and it must be the right carb for your application. Mine has a one year only(1971) high idle solenoid. Please don’t try to cut corners on the rebuilder or pick up a newer “rebuilt” carb from a box store.

Good luck! KC

 

Holley makes a quadrajet replacement carb that is pretty close to a direct fit.
If you don't have a workable quadrajet check out the Holley.

 

I'm looking into that now myself, I always thought a TBI injection as being a pretty small upgrade but im realizing the devil is in the details and it may be a winner for the tuning and reliability aspects alone. I have my current setup dialed in nice but now ill have to start all over again.

 

This is the carb im running now... 24 corner idle adjusment screws. not a spreadbore carb though so you would want a performer eps or likewise intake.

This is almost half price. Couldnt even tell mine was used. Came in original packaging with all new accessories

https://www.holley.com/products/fuel...ts/FRHR-680-VS

 

Okay, I talked to Lars. Unfortunately he no longer does overseas orders and doesnt have any i can buy outright. So can anyone point me to a Holley that would be a good fit for me?

 

750 double pumper

 

Only Holley that will fit a spread bore intake is this

9895

 

Or this
80555c

 

Brawler 750 is the best bang for the buck. Better tunability then a regular Holley

 

Doesn't fit a spread bore intake

 

That brawler is almost the same as the quick fuel HR im running and linked above. I like the tun-ability myself..

 

True That. So put a better manifold on too

 

Yup, intake manifolds are affordable and definitely worth the effort. Most center the carb while the factory manifold is not centered. Yes, this changes air filter fitment. But, think about it. Relatively even distribution to the cylinders can't be a bad thing!

 

Another option is to learn more about how to work with what you have and see if it can be made to work as is.
Sometimes looks can be deceiving, but from the pics it seems to be in decent shape and may be able to be tuned as is. Again a CSM for your car would help rule out if you really need a different one.
Also because the Quadrajet was used on all Gm products(along with others like Ford/Dodge)look around and see if you can find someone there that may have another brand of GM that can help you gain more knowlege and help with maybe a rebuild. Heck, even someone that works on European stuff could be of some help when it comes to the actual mechanical part of it.
If you can find someone to give you a hand make sure to come back here with any questions. Lots of knowlege here and usually someone can figure it out.

 

The Q-jet is the best carb out there, but parts availability is tough, and very few people really know how to tune one. Buy Cliff's Q-Jet book and learn to tune it yourself, and you will be far ahead. A good Q-Jet can be worth more than fuel injection, some good ones now run $2000, and it can work just as well as EFI. Same gas mileage, HP, etc. They'll flow well up to 550HP or so. They get a sour reputation mostly because someone in the past tried to tune them like a Holley or some other bad trick idea. GM had a 1000 different variations of them. You need the right code # one for your car. Hopefully it is still there. If it has been commercially rebuilt, they probably mixed up a lot of parts from different carbs, and may have permanently ruined it. If it is messed up you will likely need an expert like Lars or Cliff to help straighten it out. Once it is set correctly, it will stay that way for years. They do not tolerate very low vacuum race cams well, and engine mods can be hard to re-tune. The main way EFI can beat one is making an adjustment on the computer faster and without getting dirty, and EFI is much easier to tune for driveability on the choke circuit.

The Holley is the second best out there, but they are readily available, can be respectably tuned by almost everybody. Parts are readily available almost everywhere. Tuning for HP and getting rid of bogs is easy on a Holley. Easy is a good word for a Holley. But you must have the correct model to start with, and tuning the idle-cruise "driveability" circuits can be very difficult. They will make the same power as a Q-Jet but are much easier to tune to get it there, so some claim they make more power. But they are difficult to get the same gas mileage or driveability as a Q-Jet. There are a dozen or so variations. And you can tune a Holley for almost any kind of low vacuum race cam. Holleys can be easily re-tuned for most engine upgrades.

The Edelbrock AVS is like the third choice. One size does not fit all, they only have a couple of versions. So it rarely works well out of the box. Tuning kits are more available than Q-Jet but less available than Holley. They are actually easier to tune on top of the engine than either of the two above. But even in the long run they never seem to dial in as well as the other two. With some work, they can be tuned to drive as good as a Q-Jet, and give good mileage, but a Holley usually out powers it. They just don't seem to have a major strength unlike the other two.

In a word:
QJet = great driveability
Holley = easy HP
AVS = ??? cheaper maybe??

With any kind of carb tuning these days you should consider an AFR meter.

 

Bummer on Lars not being able to help you because it’s hard to beat the original QJet for under 400 horsepower.
The Edelbrock is a universal carburetor as is a Holley and may need a tuning kit and some tuning along with a 2101 intake or the new EPS intake but they will work great , you will need Edelbrocks heat insulator gasket and a kit like this to get you started with the low fuel line hook up and maybe upgrade your valve covers at the same time for the breather tube
https://www.jegs.com/i/Edelbrock/350/1407K2/10002/-1

now if you went with a AVS2 they have annular boosters and are as close to Fuel Injection as you can get with a carburetor, here’s a link for the 650 version
https://www.jegs.com/i/Edelbrock/350/1905K1/10002/-1

I’m actually testing some Edelbrocks against my Quadrajet on my 1980 L82 right now just for conversations like this and I’m currently on a 1406 economy electric choke 600 and with the choke setup it starts cold and runs equal enough that I don’t think anyone could tell by driving it that it’s not the QJet and this economy 600 version is only 1 mph slower than the Quadrajet in the 1/8th mile almost 2 in the 1/4 out of the box setup no tuning so I might be able to match the Quadrajet mph with a little bit of tuning , I’m happily surprised how close it is.
I have a 1405 eBay core,1406 Craigslist 60.00 special (being tested right now),1407 eBay the seller stated bought new and ran bad and took it off (disgruntled Edelbrock employee as it totally had the wrong parts inside, lol

) , EPS800 eBay core missing choke and a AVS2 650 new from Jegs to play with just for fun and frolic .

 

country is ES i assume estonia. makes it far more difficult to send it to somebody for rebuild. buy a rebuld kit. replace the top gasket and accelerator pump diaphragm. import duties on 25 dollar carb kits are far less painful. this is not that hard a carb for a backyard a$$hole to repair himself

 

The 650 Holley Spread-Bore with vacuum secondary will simply bolt on and make you smile. This carb is a Qjet replacement. It even has the little choke arm that will connect to your stock manifold choke system, so no wiring required for an electric choke.

 

https://allamericancarburetor.com/. I've heard good about these guys.

 

Ok rather than switch to a Holley, I would try to find an original Q-Jet.
A second one if you prefer.
They are almost impossible to beat as far as throttle response, driveability, reliability and gas mileage vs the other types mentioned.
Especially if your engine is anywhere close to stock.
A Q-Jet can be difficult to mod however, so if you have engine mods, depending on what they are, it may be easier to switch to an Eddy or a Holley. They are easier to self-tune.

If you do not have the GM Historical archive information for your car, you need it.
I attached a 1974 here.
Deep in there it has your carb #.

It says your stock Q-Jet is a 7044502. L48, auto. It is a different # if you have a 4spd. You should check the number on your drivers rear screw to be sure the one you have now is correct anyway.
I am not sure why you think you need to change it, but it may just need tuning or refreshing,
You will not gain HP by changing the carb, unless you current one is not working "right".
They are not that hard to find. You could buy one off e-bay and rebuild it yourself. It's a good learning experience.

You can find good parts here:
https://www.carburetion.com/CarbNumb...Number=7044502

If you prefer to buy a used Q-Jet they are out there:
Here's an e-bay one for $70 but you never know what you get used.
https://shorturl.at/epK7w

If you prefer to buy a complete Q-Jet , that is quite likely to be done right, try these guys:
https://quadrajetpower.com/chevrolet-1974-350-7044502/
$549 rebuilt correctly, To me that is a better buy than an $800 Holley.
If you have a few engine mods, they can tweak it for you.
A Q-Jet can work well to 400HP and a little beyond, if you work it correctly.

I'll also attach the GM Q-Jet service manual.
You'll need that too.

Good luck.