[mgarblik]

A Q-jet will provide the best combination of fuel economy, power and driveability. The triple venturi cluster design on the primary side gives sophisticated fuel delivery that rivals fuel injection when working right. Everything will fit and look right on your Pontiac with this set-up. The Edelbrock knock-offs will run of course, but will require a bunch of "rigging" and "hacking" to make it fit and operate correctly. Fuel mileage will never come close to a Q-jet. They are shiny though, won't dispute that. BTW, tuning parts for the Ederlbrock carbs are VERY expensive and hard to get. Just went through tuning a pair of AFB's and had well over $200.00 in jets and metering rods by the time I had a decent tune on them.

[Cliff R]

"If it’s not a restoration why pay big money for an inferior early Q-jet?

Plenty of reasonably priced ‘77 and later Q-jet cores are out there and are a far better design."

+2, 3 and 4.

Since I have no dog an anyones fight (retired from carb building) I'd stay as far away as humanly possible from a Holley Street Avenger (or any of their "bottom of the barrel offerings") and even further away from an Edelbrock AFB or AVS clone. The only good sound any of those make is when I "tink" them off the dumster outside the shop or hit the round trash can by the shipping table with one of my famous "hook shots".

I get locals crawling up here ALL the time with that junk on their "fresh" engine builds BITCHING about all sorts of issues. Then I take a look at the "cobbled" up install where they cut the original fuel line with a hack saw and ran 3' of black rubber hose around to the back of the carb for a fuel supply, often out over the valve cover so it can pick up heat from the exhaust along the way and rub on just about everything it between....LOVELY!

I love stories so here's a good one. Local guy shows up with his engine builder and they can't get their brand new out of the box Edelbrock AVS to do anything right. He is "dead heading" it with a Holley mechanical pump and a regulator and it starts "loading up" after sitting at idle for about 1-2 minutes. I removed it from the engine, put it on my test engine (with a return) and cranked the fuel pressure up to 10, then to 12 psi and it idles fine and doesn't load up or flood at all. Put it back on his dead-headed set-up and clear down to 3psi with the regulator and it floods out. How are you going to fix that? I asked him. He said it didn't do that with the stock mechanical pump but he got a bloody nose when the car nosed over top of first gear because the stock pump wouldn't feed it (454 about 430hp).

He also noted that aside from flooding after it sits at idle for a minute or so that fuel economy is HORRIBLE, and it's got a stumble going into the secondaries that will NOT tune out no matter how tight they wind the spring on the top flap. I ran into the exact same scenario when I drag strip tested them. I was finally able to get rid of the huge stumble by winding the piss out of the spring, but never completey got rid of the noticable transition onto the secondaries. We ran it on two different vehicles on that private track outing and it was the SLOWEST of all 8 carbs we carried along that day, on both vehicles.

I know, I know, go to a car show with 250 cars present and 238 of them will have an Edlebrock intake topped with one of those pieces of bovine excrement, or even worse a Holley Street Avenger.......because they are shiny and cheap.........FWIW.......

[carbking]

Originally Posted by Cliff R

I know, I know, go to a car show with 250 cars present and 238 of them will have an Edlebrock intake topped with one of those pieces of bovine excrement, or even worse a Holley Street Avenger.......because they are shiny and cheap.........FWIW.......

Cliff - tell us how you really feel

How about "equus ferus caballus excretement"?

Jon

[carbking]

A continuation of my previous post (dog-gone telephone):

Obviously your car, and your choice.

However, the Q-Jet is a "spread-bore" carburetor.

I think the imitation is a "square-bore" carburetor.

USE THE INTAKE DESIGNED SPECIFICALLY FOR THE CARBURETOR OF YOUR CHOICE.

Do NOT just buy the wrong intake, and ATTEMPT to then install the carburetor with an adapter plate and mis-matched mounting gaskets; or your next post might be "I cannot get the idle down to a reasonable RPM" (read as vacuum leak from carb to adapter to intake)!

Take a look at the second line in my signature block (it also applies to intakes).

Jon.

[i82much]

i have a street avenger 770 that i bought a year or two ago, runs great out of the box. just adjusted idle screws and choke.

[Tom Vaught]

No use for the later Holley Offerings. I still buy the older ZINC Holleys at swap meets and have them dichromated after proper prep.
At least there, you can make sure the carbs are not damaged in shipping, (the latest 421 SD intake manifolds had excellent shipping boxes).

Tom V.

[Cliff R]

+2 on tuning the AFB clones. I had a customer send me two "Marine Q-jets" that turned out to be Webber built AFB Marine clones. Instead of sending them back, which I typically would do if I didn't break them on one of my "hook shots" i decided to dive into them.

Right to start with they had the correct part numbers on them, and original to his twin 454 powered boat. However, when I checked them over closely they were NOT the same for jets, rods, IFR's, air bleeds, etc. So now the quandrum, which one do I copy to make them IDENTICAL units.

Thankfully he had tagged them and noted that his fuel meters showed one fo them using considerably MORE fuel than the other, so I started there. I was able to obtain the same jets and metering rods, and "modify" everything else to make them identical twins. However, on my test engine they didn't run all that great, very rich at idle, and noticable hesitation and overrich condition right off idle thru transition.

So I went into the parts catalog and bought multiple jet sizes and dual tapered metering rods for them and went to work. When I was done they were FLAWLESS, but I had several hundred dollars tied up in tuning components as mentioned above.

The owner got them, and few months later gave me a call telling me that they were also flawless on his end and his fuel economy was a LOT better than it had ever been since he purchased the boat.

Sadly we could have prepared two Marine Q-jets and done better, but his intakes had no provisions for divorced chokes and sourcing out Volvo Penta e-choke Marine Q-jets can be difficult and expensive......

[Rob in NH]

Wow, never knew how this carb would get all the carb guru's upset, Cliff, have a cup of coffee and relax LOL.

[Kenth]

Originally Posted by Rob in NH

Wow, never knew how this carb would get all the carb guru's upset, Cliff, have a cup of coffee and relax LOL.

With some 40+ years of experience with these things you may learn the benefits of different carburetor designs.

[carbking]

Originally Posted by Rob in NH

Wow, never knew how this carb would get all the carb guru's upset, Cliff, have a cup of coffee and relax LOL.

Rob - as I posted in my last post; if you are happy, then that is what matters.

As to being upset; I didn't see any posts that were upset with you.

Many of us have been professionally working on carburetors for decades (I built my first Holley in 1959). Over the years, we learn that virtually ALL carburetors have a "best" in one or more categories. (And if there is a "best", then there certainly must be a "worst").

When a question such as you posed is asked, we attempt to give the original poster the benefit of experience.

The internet is full of conflicting opinions, and that is fine. One just has to determine which opinion is correct.

Many of the folks here (Cliff for certain, I don't know about Kenth) are retired, and as Cliff stated "have no ax in the ax fight (or maybe it was "dog in the hunt), same cliche". I should have retired two decades ago, but having difficulty finding a buyer for the business (looks like son will take over part of it).

The point being, we are basically offering free advice. What is done with that advice is up to each individual.

When selecting a carburetor; one should look at several categories, depending on one's eventual use:

(1) Initial cost (the ONLY category in which the e imitation is "best")
(2) Service cost
(3) Performance (HP)
(4) Performance (driveability)
(5) Fuel economy
(6) Reliability

(Professional opinion) the e imitation will finish dead last against virtually all other entrants in categories 2~6.

I know you have posted you are currently happy, after all, the car is running; but since you now have time, I would highly suggest looking for a rebuildable Q-Jet and a manifold to accept it when you frequent swap meets.

Jon

[Onebad77ta]

Q-Jet all the way for me.
If I could put a Qjet on my Ford junk I would.
A lot of years back when I did my first 455 I asked Cliff for some tips/tricks because I have been doing stock rebuilds on Q-Jets for a long time with great success but didnt have much knowledge of doing performance modifications to them.
Cliff happily obliged and told me how to do some things which I did and my rebuild/ Modified Q-Jet ran flawlessly and out performed my box stock Holley in every way.

[carbking]

Originally Posted by Onebad77ta

Q-Jet all the way for me.
If I could put a Qjet on my Ford junk I would.
A lot of years back when I did my first 455 I asked Cliff for some tips/tricks because I have been doing stock rebuilds on Q-Jets for a long time with great success but didnt have much knowledge of doing performance modifications to them.
Cliff happily obliged and told me how to do some things which I did and my rebuild/ Modified Q-Jet ran flawlessly and out performed my box stock Holley in every way.

Ford used some Q-Jets in 1970 and 1971 on the 429.

They also used TQ's on some of their 460's

Jon

[PunchT37]

Originally Posted by carbking

Ford used some Q-Jets in 1970 and 1971 on the 429.

They also used TQ's on some of their 460's

Jon

Mopar even used em on their police 318`s and the 360 truck engines before they went to the Magnum engine.

[NeighborsComplaint]

Edelbrock's AVS2 also comes in a spreadbore configuration (1912/1913 Series).

[Kenth]

Originally Posted by NeighborsComplaint

Edelbrock's AVS2 also comes in a spreadbore configuration (1912/1913 Series).

Looks like squarebore to me.

https://www.edelbrock.com/catalogsearch/result/?q=1912

[64speed]

I was/am having very good luck with the Brawler from Quickfuel. YMMV

[carbking]

We seem to have deviated "slightly" from the original question (as we often do).

OP - many of us have suggested the Q-Jet. One reason is that it is a "spread-bore" design. By 1970 (well, 1972 for Chrysler products) ALL US producers of automobiles had adopted the spread-bore design for virtually ALL V-8 engines, because of the features I mentioned in my first post.

Exceptions (square bore design) were used only on engines that the manufacturer knew had a good chance of being raced (street driveability of less concern) or trucks which would be on the primary side with lower vacuum than a passenger engine.

Give some consideration to the reasons ALL of the car companies went to the spread bore design.

Again, your car, your choice.

I have a spread-bore on my own 350 Pontiac, a Carter TQ, and I have 150,000 carbs to choose from (none of which are imitations); so really believe in what I have recommended to you.

Jon

[shaker455]

Originally Posted by Rob in NH

I'm going to replace my carb soon and was wondering what I should get for cfm. Its a 350 2bbl soon to be a 4bbl.

Rob, that night I came over with my GP to your house, I thought you showed me a Qjet for your car you had already?
Jeff

[Rob in NH]

Originally Posted by shaker455

Rob, that night I came over with my GP to your house, I thought you showed me a Qjet for your car you had already?
Jeff

Its a chevy carburetor

[Cliff R]

"Ford used some Q-Jets in 1970 and 1971 on the 429."

Those were and are EXCELLENT units. A factory "hot rod" carb right off the bench. The intake Ford made for them was also a really nice part, with wide plenum areas and very well design runners for effectively feed the 429CJ engines.

One can learn a LOT from looking at what the factory did on their "high performance" Quadrajet carburetors. The Pontiac Ram Air, HO, Super Duty, Buick Stage 1, 1969 Chevy 350/350hp, and a few others fall into that catagory........