HOLLEY CARB ADJUSTMENT

DOES ANYBODY KNOW HOW TO ADJUST A HOLLEY 600 CFM CARB? PLEASE RESPOND TO snipped-for-privacy@NGC.COM

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HAND JOB wrote:

Yup, everyone in here knows how, no big secret. Now if you turn off the capslock key, and follow your own post's thread, someone MAY deign to tell you the hallowed secrets of Holley. If you think someone is going to spoonfeed your ass by writing up a manual and mailing it to you you have a long wait coming.
Moron.
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Two choices:
Get a manual and follow the directions. If you don't have a manual, get one, or close the hood, step away from the smoking Holley junker and pay someone that knows what they are doing, which leads to solution #2,
Scrap the Holley and put the original Q-jet on there and the vehicle will run like it was supposed to run. Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director '80 Carousel Red Turbo T/A, 27k orig. '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 143k and still going....
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Bigjfig wrote:

Ok, I don't get it. Everone I know refers to them as "Quadrabogs" or "Quadrajunks". I've never tried running one. Now if they are so good why is it that 90% of them are replaced by Hollys or some other aftermarket carb? Not trying to start a flamewar here, just curious. I happen to like Thermoquads on my old Mopars but there too are a huge number of folks who think I'm nuts.
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I haven't been flamed for reposting anything in a while....I'll offfer this: I'm a big believer in the humble Q-jet. Complex & hard to understand BUT when you do understand it, it is the most "tunable" carburetor made. AND for the people that say it is just something to get groceries with, I offer a couple of photos:
http://home.mindspring.com/~andywarren/_uimages/100_0748_8.JPG
http://home.mindspring.com/~andywarren/_uimages/100_0747_8.JPG
This little Q-jet belts out over 500 horsepower!!! No, it's not my car just one I saw at the local dragstrip. You can tell by looking at the underhood goodies that this guy could afford a Damn-Good carburetor. and that is what you will see sitting on top of his motor... Andy W.

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The reason why they are replaced is due to stupidity and ignorance and nothing else.
Fact is that for a GM car, there is nothing better. Most folks will never "outfuel" a Q-jet that they will "need" a Holley.
Overcarburetion of a muscle car engine is one of the biggest mistakes most folks make. A good, tuned Q-jet will run with the best of 'em and put any Holley to shame.
Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director '80 Carousel Red Turbo T/A, 27k orig. '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 143k and still going....
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If I call them Q-junks Joe gets all bent out of shape. Joe and a few others here think the Q-jets 4 venturi carbs are best ones made. I'm for a totally different camp. I'm a Holley man.
Whenit comes to racing applications Holley carbs have more parts avaible to tune your set up. They have different styles of main bodies, base plates, float & fuel bowls, not to mention metering blocks. If you look at carbureted classes in professional motor sports you don't see a single Q-jet. You see a lot of Holley, and Holley-ish designs.
With a Q-jet 4V air horn, you really have to be a guru to do much with it. They are harder to make adjustments on, require far more time, & don't react well to modifications unless your Mr.Guru that knows what not to do.
If you notice I keep pointing to the 4V types (what most call a 4 barrel). That is because the 2V types (2 barrel) carbs that Rochester products made are some of the best 2V's out there. A lot of people don't understand that. Even the 80's smog versions of the 2-V's will flow good, and will work great on V6 & I-4's. They also prove more stable in events such as demolition derbies then most 4-V types of carburetors.
Some People such as Joe will argue about WHY all of the Big 3 offered Holley's from the factory on some of the Most Powerful Bone Stock cars they sold. Or asto why their factory sponsored race teams used Holley's.
When it all is said and done Joe is right on a few things. Too much fuel, or too much air will kill performance. Being 50 to 80 CFM off won't do much bad. Being over 100 to 300 off will. Yet on that same token going from 300 CFM to 800 or 850 is what bogs out a motor. Which is what happens with a Q-jet. Usually older units with worn springs and such. Not to mention, far from 'popular' belief, that much flow going thru a 350 or larger block with factory size exhaust is a mistake. It another factor in the bog syndrome. The engine is being forced to inhale more then it can exhale.
Charles
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Also remember that ALL three Big 3 bought the Q-jet from Rochester.
And, the 429 Cobra Jet Ford used the Q-jet in 1970-71, as well as late 80's Dodge trucks and police cruiser Chryslers.
The Q-jet gives far better fuel control than any Holley ever could. Holleys were offered on the GM stuff for marketing more than "performance".
At one time, the folks at GM decided to take off the Hurst logo on shifters. The marketing folks started screaming. Why? Is Hurst a better shifter? Not really. But the name sold and they wanted it. A stick on a sack of potatoes with a Hurst logo could have been used and the marketing folks would be satisfied. LOL.
Remember why they are in business :).
Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director '80 Carousel Red Turbo T/A, 27k orig. '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 143k and still going....
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Joe:
Are Hurst shifters better? Yes. Why? not only are the shifter sticks stronger then hollow tubes, ofter they were shaped different. But the stick is just a stick. To truly have a Hurst shifter, you have to have the lower section. Which has positive, adjustable stops. Which when racing keeps you from over throwing. That means pushing the stick too far forward.
Hurst also makes some damn fine shifter assemblies for automatics. Especially if you drag race with a automatic. A Ratcheting Shifter is nice. So is a shifter with positive lock outs. GM Automatic floor shifters are ok. They were never intended for people who shift gears hard and in a hurry.
A well cared for Q-jet may be better on a stock or close to stock engine. I disagree when it comes to modified engines. Sure some people run them. I have never seen a Q-jet that flows 1050 or 1150 CFM. Also why does GMPP include them on crate engines? Engines that are supposed to be the best GM engines out there? Really they are better then the majority of what speed shops build.
So what's your view on the Q-jets made by Carter? They were OEM installed, and I doubt for marketing. Very few people are loyal to Carter carbs.
Charles
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Charles:
Bear in mind that GMPP is a marketing thing, not a restoration thing. So, they will give the public what they "want" or think they "need". The public THINKS it needs a Holley because it's been told so by marketing folks.
GM is a very reactive (not proactive) marketing department and it takes them a while to catch on. In the Service Parts arena, they will put out programs they think parts people want. A Holley carburetor on a GMPP engine is one such endeavor. Also, GM (Rochester) stopped making Q-jets years ago, so source of supply is an issue. There's no choice but a Holley for the volume of applications they want. Sure they could go to Eldelbrock, but they'd basically be buying their own design back from them, and they won't do that :).
Parts people probably asked for more value oriented brake products for dealer/non warranty service. So GM goes out to Raybestos (Dana) and says they want a line of DuraStop products. What the consumer and dealers get is the same PG grade product at a much higher price than the dealer can buy at a local parts store themselves on a per part basis! LOL. The answer SHOULD have been to offer a Delco Moraine made pad with different quality lines, a good, better, best scenario, with maybe the best line being outsourced (ceramic product from a top end guy).
As for Hurst better, yes, I like Hurst shifters. I think it's a cool touch in my '79 T/A to have the "HURST" logo on the shifter AND it's factory equipment. Is it the BEST Hurst for that car? No way, I'm sure back in 1979, there were better models of the Hurst shifter that could have been fitted, but cost factors came into mind and the actual 1979 Firebird buyer just cared (if at all) that he/she was getting a Hurst shifter (one less thing they'd have to change) with the car.
Carter versus GM Q-jets: This was done because Rochester couldn't keep up with the demand for them in the heyday. It's a well known fact (documented by many) that the GM made Q-jets are far superior than the Carter iterations. As was typical with Carter--most of their stuff was junk too. How many stalling, bucking, fuel sucking Chrysler cars with Carter carburetors did you work on in the 70's and 80s? :).
The advantage of a Q-jet is that it is a wide range carburetor. It can perform on the street and strip very well. A Holley may perform well on the strip, but over the long range, it will not. Also, most folks don't run strictly strip cars (of course some do), so they have a carburetor that's good only 20% of the time. LOL.
Besides, Holleys require adapters and all sorts of "make fit" parts to fit a GM car. A Q-jet looks clean, neat, and works without such issues, because it was designed to be there.
You have arguments at both sides of the camp, and both are valid, but on the whole a Holley loses to a Rochester in more ways than one.
Ask Doug Roe about that. He's a vehement fan of the Q-jet and his book is worth reading, and he's on the ball with these things.
I like Rochester for the same reason I like Pontiac, and also Tecumseh small engines (besides the fact that the latter two are Indians and have cool logos...lol):
The work, and they work well. And they are unique in that they do the job better in a better way :).
You'll get this argument in small engines with "Briggs vs. Tecumseh". Fact is, I run both on my equipment. The Tecumseh engines (and half of them were salvaged from the curb) run better, stronger, start easier and are a breeze to fix. The Briggs, while fine (I have a few and they're ok) are cranky, slow to start, choppy, poorly put together/screwed together and just look tinny.
I did salvage a 1200 PSI gas pressure washer for $35 with a Briggs 3hp and fix it for $5 in parts. LOL! Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director '80 Carousel Red Turbo T/A, 27k orig. '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 143k and still going....
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you want answers stick around and wait for them to be posted instead of handfed to you in email.
http://www.fordmuscle.com/archives/1999/12/holley/index.shtml
http://www.camaros.net/techref/articles/holley_2.htm
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If you were smart enough to operate a keyboard and turn of the all caps key. then maybe Someone would tell you to go to the bookstore to the automotive section and buy a book on tuning Holley carbs.

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