Qjet all the way.

 

Quadrajet for two reasons: 1. You already have it. 2. Qjets typically provide better fuel economy while remaining competitive performance wise.

 

QuadraJet hands down. It's not as easy to work on as the Holley but the throttle response for street driving and better gas mileage make it worth the effort. Plus there's nothing like the sound of a Q-Jet at WOT.

Sounds like both carbs need some TLC though. If you don't have any experience and plan to do it yourself then start with the Holley, it's simpler to work on. That's assuming the throttle shafts aren't loose. If that's the case save yourself some grief and buy a new or rebuilt carb. I've had good luck with the Summit QuadraJets.

 

At this level any properly sized carb will perform about the same. If you have a Qjet and a Qjet intake then use that. If you've never rebuilt any carb one is just as hard as the other. What it would come down to me is cost and since you alreay have the Qjet setup just refreshing that one would be the cheapest and make the most sense.

The most tedious part of rebuilding it will probably be cleaning it. Purple Power and a denture brush should be about the cheapest easiest thing you can use for that.

 

thanks for looking at my question. my question is which would be preferred for a (at the moment) stock 69 impala 4bbl 350. holley 4160 or stock quadrajet. i got the holley over 5years ago so im positive it needs rebuild but looks very clean and the quadrajet has been rebuilt with a stock kit, but it sat uncovered over 2 years and was seized with gunk up until bout 2 months ago. i had the kit installed by a brother in law and is currently on the car. it fires up, but havent had time to tune. I just dont want to mess with anything if i dont have to. i know theres fans of both makes of carbs. dont have enough experience with moding or rebuilding to have an opinion. usually would just replace parts but now am interested in rebuilding. P.S. i have read through other posts that were similar, so I can say that my car is mainly a sunday beer run car. wont see the strip nor showroom any time soon. Thanks in advance.

Depends on you proclivities and abilities. The Qjet will deliver better mileage than a Holley and when set up be someone knowledgeable and patient will deliver equivalent performance. But in the the hands of someone not experienced in carburetors in general and Qjets in particular they can be really hard to set up and very frustrating as they are very sensitive to the details of each and every part. Parts are harder to come by than the Holley. These are really great carbs, but you've got to understand them, they don't respond very well to small errors in their set up.

The Holley is easier to set up and get it to work mostly because it works pretty well even when not built with particular care. It is much more tolerant of someone still learning about carbs. Besides, parts are available everywhere, it would seem in every grocery store. These are also great carbs and will respond in knowledgeable hands, but they also function OK over a very wide range of not quite right set ups.

Bogie

 

I love my Q-jets

 

I rebuilt a q-jet for my old pickup and had to fab a tool for adjusting the float height. it was a simple 14 inch socket 14inch well. and a short peice of 14 copper tubing smashed with a hammer to fit over the small flat head screw driver tipped screw. took some trial end error but it finally worked very well.

 

qjet

quadrajet all the way!
Every Holley i ever had seemed to waste alot of gas.

 

No doubt about it, a properly overhauled, setup QJ is the ticket. Unfortunatly there are too many shade tree mechanics who think they are QJ experts. I would venture a guess that there are very few QJ's (short of being new or professionally overhauled) out there that meet the above criteria.

Vince

 

which would be preferred

The only reason I would consider a Holley over a Q-jet, is if the Q-jet required an adapter to fit a square bore intake manifold. The adapters suck. But the Holley carb offers no performance advantage. Nor an economy edge. Or response/off idle performance. The Q-jet is a good carb, and unless yours is not working right I would run it as-is.

If the plugs or seat of the pants says there's more to be done, describe the symptoms and we'll give you some suggestions.

Don't forget the ignition during this- the timing curve can effect the way the car runs a LOT.

 

Q-jet.

grandpa worked at GM during the day, and fixed cars up at night. Hope he gets to teach me how to tune a q-jet. From what he and my uncle (grandpa's shop assistant) told me he could get the carbs just right and the cars would run like hell. In a good way.

 

thanks for ALL the input yall. All info is apprecieated. I'll keep checkin in. Im trying to get pics up. Thanks again and feel free to check back if anything else comes to mind, cause I know I'll proly re-read the replys a few times(got a short attention span). Peace...

 

im in the same boat as you man im rebuildin a q jet off a 74 pontiac 400 and i dont know a lot about carbs

 

I don't know about Holleys, I used to use Edelbrocks, not anymore. Qjets only. Far better carbs. Better throttle response, better starting, better economy, don't have smelly exhaust.

 

I'm no expert, but why is it that GM always put Holleys on their high performance cars, Chevelles, Camaros, Corvette, 442, GTO, etc, vs the quadrajet...

 

Cliff Ruggles can show you how to build a Quadrajet that will perform perfectly.. He wrote a book and sells the parts.. I was so impressed with his work that I bought a Pontiac 455 and a custom Turbo 400 from him...

My Pontiac 455 with a lumpy cam and Quadrajet is every bit as easy to control in hot city traffic as my 2001 350 fuel injected Chevy truck..

http://www.cliffshighperformance.com/

 

I'm no expert, but why is it that GM always put Holleys on their high performance cars, Chevelles, Camaros, Corvette, 442, GTO, etc, vs the quadrajet...

Ease of adjustability, and no emphasis on economy. GM realized the hi-po engines were likely going to be modified by the buyers.

 

im in the same boat as you man im rebuildin a q jet off a 74 pontiac 400 and i dont know a lot about carbs

The best way to learn is to rebuild a few........so your on the right path

Best advice i can give to first timers and veterans alike, Is take pictures of everything before and while you take it apart. That has saved me many times.

:thumbup:

 

I'm no expert, but why is it that GM always put Holleys on their high performance cars, Chevelles, Camaros, Corvette, 442, GTO, etc, vs the quadrajet...

Chevy put Holley carbs on their performance models, B-O-P performance models ran Q-Jets from '67 until the end of the musclecars. Ram Air GTO's, Super Duty Firebirds, 442's and 455 Stage 1's all came with Q-Jets. The "lowly" 454 LS-5's and 390HP 427 Vettes ran Q-Jets too and a well tuned otherwise stock LS-5 '70 Chevelle with headers and some traction was nothing to be laughed at.

 

A Holley is a high maintenance carb, if you use it daily or lots of miles.-always something.

 

in your application - the QJET sounds good

 

A Holley is a high maintenance carb, if you use it daily or lots of miles.-always something.

Only if you don't do it right the first time, or use crappy gas/filters.

Any carb can be made to perform really well, it all depends on what you are familiar with. No one is made a carb expert by doing a simple rebuild or swapping around some needles and jet either. Any 8 year old with patience can do that, it takes some one really exceptional to build a great carb. I would be more concerned about finding a reputable builder than which type of carb he would recommend.

 

I prefer a good Q-jet on a street car. But hard to get a q-jet setup right.

needles, jets, rods, hangers, plugger length, float level, throttle shafts, old castings, leaking bases...........

cliff sells them for 500 plus a 6 month wait. summit sells them but it is pure luck to get a good one.

I ran a q-jet for a few years, but went back to the holley for a more consistent running carb with slightly better power and slightly worst mpg.

For a simple, cheap, durable carb. get a Holley 750 3310. works on a 283 to mild 496. Can pick them up for $250 to 300.

I have two 3310's and I drive them daily (not at the same time). never had to touch them for over 6 years now. nice carb.

 

Building the carb itself is straightforward. It's the tuning that requires some knowledge.

In my opinion, if an individual takes the time to learn the basics, practice on a carb (other than his "good" one) by taking it apart and reassembling it a few times, that he will then be capable of tuning a carb just fine, given some direction.

You should start w/a good carb- not some mismatched pos from eBay or the flea market. In the case of a Holley, this means the metering blocks and plates need to match the carb, all the parts present (unless you already have the missing parts or can get them AND the missing h-ware is reflected in the price).

You don't want someone else's idea of a "modified" carb w/drilled out passages or orifices, avoid carbs w/holes drilled in the butterflies, and be sure that the carb matches up well to the application in size and type (vacuum or mechanical secondaries, choke or not, square or spreadbore, correct linkage for the vehicle/trans, etc.).

With a Q-jet, you want to pay attention to how well the primary throttle shaft fits the base plate. The shaft (even though it's teflon coated) will wear into the base plate (creating a vacuum leak) if the wear is significant. There are bushings available to fix this, or you can send it out to be done.

The vacuum "break(s)" located on the passenger side of the carb need to be checked to be sure they're good and will hold vacuum, otherwise the secondary actuation will suffer and you'll be paying for replacements.

The Q-jet is known for having leaky primary and secondary wells. These can be fixed by several methods, depending. JB Weld is always suggested for this, but in my experience that fix will not last, eventually the epoxy will loosen and the leak reoccurs. A permanent fix is possible but is outside this short discussion.

A lot is made of the "big" Q-jet. It's rated at 800 CFM, but truth be told, you'll very likely never know the difference between a 750 and a 800 CFM Q-jet. The 800 was even used on later ('86 was about the latest non-feedback Q-jet, IIRC) 4.3L V6's, and I have taken 750 CFM Q-jet carbs off of 455's, so that should tell you something!

The Q-jet has a few "quirks" about it that will frustrate first-timers, correctly placing the primary needles inside the jets will frustrate ANYONE, for that matter- experienced or not. Hooking up the choke link can be tough at first, there are others.

I would suggest a good manual for further instructions and tips/tricks/fixes. Cliff Ruggles' book is always mentioned as one of the best, and next to that is Roe's book on Q-jets. GM factory manuals have real good info and photos, too.

There are quite a few Holley "How To" books out, I do not have a favorite, perhaps someone can offer some suggestions.

There are a LOT of replacement parts available for either carb (hell, you can build a "Holley" w/o using one Holley™ part), but this all adds to the cost- quickly- and can bring a "$10 carb" to over a $100 carb before you know it. That's why you want to test/check things BEFORE you buy.

 

I prefer a good Q-jet on a street car. But hard to get a q-jet setup right.

needles, jets, rods, hangers, plugger length, float level, throttle shafts, old castings, leaking bases...........

cliff sells them for 500 plus a 6 month wait. summit sells them but it is pure luck to get a good one.

I ran a q-jet for a few years, but went back to the holley for a more consistent running carb with slightly better power and slightly worst mpg.

For a simple, cheap, durable carb. get a Holley 750 3310. works on a 283 to mild 496. Can pick them up for $250 to 300.

I have two 3310's and I drive them daily (not at the same time). never had to touch them for over 6 years now. nice carb.

Agreed :thumbup:
The Holley#3310 is one dandy carb! as long as your cam isnt to rowdy they work on just about anything........Plus they make that cool *squish* sound when the secondaries close.

Great carbs.