[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......

[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

[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

[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........

[Cliff R]

"Cliff - tell us how you really feel "

Jon If you haven't noticed I'm quick these days to talk bad about things, which at times may include certain parts or the work of others. Back when I was building carburetors I didn't feel right about bad mouthing anything where it looked like it might be competition, or trying to steer work in my direction, etc. These days I just might tell you EXACTLY what I think about something. I also have bad cases of CRS, and even worse cases of DGS.....that's "Can't Remember Sh*t" and "Don't Give a Sh%t". With all that going on I'm pretty much smiling all the time these days!........LOL.....

[Cliff R]

On a more serious note, when it comes to carburetors the very best carb is going to be the one you spent enough time with to dial it in EXACTLY for your application. It still makes sense to spend your hard earned money in the right places, so there are options out there that just aren't that great, and other options that aren't worth two squirts of duck poop no matter how much effort you put into them.

No big secret that I absolutely HATE the ever popular Edelbrock AFB clones. Not because you can't findle around with one and get it pretty well dialed in for what you are doing. It will start well and move your car effectively from point A to point B. I hate them because there is not adjustment for the opening rate of the secondary air flaps. So IF they hesitate, stumble, bog, backfire or puke all over themselves going quickly to full throttle there is nothing you are going to be able to do about it. There is also some "cobbling" involved with installing them on some set-ups. I've had fuel line hitting the bottom of the air cleaner base issues, and difficulty running a hard fuel line to them as they are really wide in and the fuel inlet is in the left rear. Otherwise pretty easy to get dialed in if you don't mind giving Edelbrock another pay check for the tuning kit(s).

I've also ran the gauntlet with the Holley Street Avengers and not fond of those at all. They have several fundamental issues which I'll not dive into here, and just not very well made. I've had them come in here delaminating, or basically flaking off internals that are in contact with this new fuel. For sure a notch better than some of Holleys bottom of the barrel work, but certainly not even close to the HP line up. It also appears that Edelbrock now has developed and is pushing another Holley "clone". At a glance they did their homework and addressed every area that needs attention, and put an removeable bleed at every location. Time will tell how they will sort out and fall into the market, but for sure I'd look at those WAY before the shiny Holley cheap offerings.........FWIW.....

[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

[shaker455]

Oh, I thought you showed me a BOP with the intake you had

[Tom Vaught]

Originally Posted by Cliff R

At a glance they did their homework and addressed every area that needs attention, and put an removeable bleed at every location. Time will tell how they will sort out and fall into the market, .........FWIW.....

Cliff, just a reminder, you already know this:

The vast majority of the Holley Dominator 3 circuit carbs over the years were converted BACK to 2 circuit carbs Holley Dominator carbs and went quicker on the track after the Modification.

Tom V.

[Rob in NH]

I installed a edelbrock intake and a 600 performer carb, it runs good and seams to have woke up the engine.

[carbking]

Originally Posted by Rob in NH

I installed a edelbrock intake and a 600 performer carb, it runs good and seams to have woke up the engine.

Thank you for updating the thread.

It is your car, and if you are happy, that is all that really matters!

Jon

[redhawk44]

My only advice is to check and double check the credentials of any so called "expert" if you have anyone rebuild one for you. I am in a 4 month ordeal trying to get my quadrajet back from a guy. Also that quadrajet is replacing a Edelbrock 750 cfm , my buddy has almost the same motor/tranny setup and is always getting better fuel economy with his QuadraJet then I am. And his car runs hard with the QJ. if your interested in an Edelbrock I have one I will sell if I ever get my QJ back.

[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

[Cliff R]

Same square flange dual bolt pattern crap they've been pushing for decades. Sales were never what Edelbrock wanted on the AVS versions even though they have a fighting chance of working when you go quickly to full throttle. The poor sales were only because of the nearly double price point compared to their AFB clones. That fact cause the demise of the excellent run of Q-jets they made for a few years. Who's going to pay over $500 for an Edelbrock 1910 850cfm Q-jet when you can buy two of their POS AFB clones and still have some money left over for a Big Mac and a Coke? To me this indicates how cheap the majority of hobbyists and enthusiasts are when it comes to this sort of thing.......IMHO......

[25stevem]

The OP made a good choice with that 600 cfm carb. That can fill the needs of up to 380 Hp motor very well.

If you want few more top end HP add a K&N sub stack and even with a 600 cfm carb you should be running a open 3 & 14 air cleaner.

You may need to go to fatter secondary jets with the sub stack.