Why Quadrajet's are awesome part 1

[@jamieforrester4814]

I love the quadrajet on the 305 in my truck. It pulls 21 inches of vacuum at 1200 feet above sea level and gets me and average of 15 MPG.

[@JohnnyRebKy]

I always loved the Q jet. We used to flip the breather upside down and when those huge butterflies opened up it sounded awesome! I swapped it for a Edelbrock which worked fine but that loud growl from the 4 barrel wasn’t there

[@72chevelle156]

I love Q-Jets!!! I wish I had an 1150 CFM Q-Jet I'd put it on my Big Block Chevy. (Maybe I'll use 2 in the future) Once you read and learn about a Q-Jet the versatility is huge. The people that bash Q-Jets are usually the people that damage them. People just don't take the time to learn. Modifications for HP are easy as long as it meets the CFM. Plus you have the economy primary's, you can cruise 110 MPH on those alone (obviously if you're geared for it)

[@Blazer02LS]

I run Q-jets quite a bit. Never could get the hatred toward them. Once you know what each part does and how to tune it to match the engines needs they are real close to fuel injection precision. Biggest thing I've seen is people who try to tune them without understanding how they actually work. Sure isn't due to the flow rates. 750 cfm was common, 800 on the Hi-Po engines (want an 800 cfm Q, just look at the 79-84 GM light trucks in 50 state trim, even the carbed 4.3 used the 800 cfm casting)

[@OldDude04]

Blazer02LS I found out my stock qjet is 800!

[@Thevinylking69]

It was a fantastic design and a perfect fit with the spirit of GM putting the same part on multiple different cars to power everything from 305's to 500's and almost everything inbetween

[@MrBluzhound]

I love these vids! Tyler has other stuff to do (lawn mower to ‘73 Dart rear end), but talkin’ QJ’s has its priorities!

[@SGTJDerek]

I've run Holley, Edelbrock, pre-emissions Q-jets and Carters. The Q-Jet was by far the best. Once they are set properly, you don't HAVE to fiddle with them. It's set and forget. Problem now is the cost and finding them. Rebuilders want the core you are replacing and they are almost up there with the price of a custom Carb.

[@rwaitt14153]

Yes. The difference between the pre and post emissions q-jets is night and day. I run a q-jet and I have gotten all sorts of grief because they think I am running one of those 80's spaghetti monsters. Those things are garbage. I run an early 70's QJ and it is great. Trading "up" to an aftermarket Carter/Edelbrock or Holley doesn't gain me anything. However, old style QJs do have a downfall. Vacuum secondaries. The mechanical secondary Holley is a nice option for those who want all 4bbls and they want them RIGHT NOW. There is a physical limitation in what the vacuum-operated system can do quickly and a mechanical system solves this. However, that mechanical system had better be dialed in exactly perfect or it is just a big waste of money. For most applications? Go vacuum. For showing off to your friends? Go vacuum. For serious stuff? Then go mechanical. But only with a MT. For AT? Go vacuum. I'm not even sure how any of this would work with a super/turbo on it blowing through. Probably not good for anything without requiring further modifications would be my guess.

[@GregHuston]

The 75-79 Q-jets are supposed to be some of the best. Better fuel metering than the older Qjets.

[@brucegillies1694]

I went with Holley first, I could get most categories right on but could not get them dialed in all categories, idle , off idle , mid range , 3/4 throttle , full throttle , fuel economy , and leaks , a very adjustable carb. Worked on them for several years! Then on a project with a Q-Jet fiddled with it and really didnt get much improvement so I sent it to a custom carb co. What I got back was amazing , It WORKED for me beautifully ! That was 35 years ago ! But planning on refreshing this carb for more trouble free years !

[@vulgarhyena9616]

Thank you so much for your detailed quadrajet videos! Everyone kept saying "put a holley on it" and I didn't listen and now that I have this 750cfm quadrajet running correctly on my 1970 c20 350ci everyone gets in and says holy $h!t!!?? This has a quadrajet?! This thing seriously screams! My main issue was my devorced choke was blocked off on the manifold and someone rigged a real light spring to hold the choke flap open and it was closing on me, removed it completely (for diagnosis) and it seriously RUNS Thank you so much for taking your time and sharing your knowledge on this geniusly designed piece that so commonly Misunderstood, I can't thank you enough!

[@johno9507]

I absolutely love the Q-Jet on my Aussie Holden 5ltr V8. Even on the coldest mornings, just one press of the pedal to activate the choke and she fires first time, every time! 😀

[@stevepayne3745]

My family had numerous vehicles from the late 70's into the late 80's, and three of them were completely stock quadrajets.... A '79 Buick Electra with the 350, a 1984 Buick with the 307 and a 1986 Chevy 305....vs. Our Fords that were always strangled with crappy carburetors, these stock quadrajets yielded performance, fuel economy, drive ability and hot start performance on par with computer controlled EFI.... Yes, they were THAT good... Plus, flip the lid and enjoy that quadrajet music when the secondaries open... Even in stock form, those play awesome music!

[@TylersNeighborhoodGarage]

Absolutely correct.

[@stevepayne3745]

Yes...the Chicago area instituted emissions testing in the mid 1980's.... Our Ford pickup with the 4.9L inline 6 and 1 barrel carburetor.... Had trouble passing the emissions test even new... Contrast that to our 1986 Caprice 5.0L quadrajet... No carbon monoxide at the tailpipe, and hydrocarbon emissions in the single digits... In terms of parts per million.... That tiny two barrel ensured awesome idle stability and combustion under low load, while those massive secondaries yielded sparkling WOT performance... And sound....quadrajets are so tuneable in their fuel metering that minor engine modifications mean they need to be recalibrated....but tuned correctly, there really is no better carburetor for the street... IF properly tuned... I bet the engineering genius Ed Cole. President of GM when the quadrajet was introduced... Had a major influence in development and propagation of the quadrajet... Also the father of other icons like the Chevy small block V8, and the catalytic converter which, in the end, has enabled sparkling performance AND low tailpipe emissions

[@briang4470]

I completely agree with all your points in this video. My belief with cars is that if it's a hotrodd that I'm going to work on alot then I will run a good 650-750 holley depending on application but in a stock type of vehicle that I dont plan on working on all the time or in something like a tow truck, then I will always choose a quadrajet. The throttle response and driveablitity of a quadrajet is so hard to beat and in something like tow truck or a box truck or just a really heavy vehicle, the quadrajet works really good because you can floor it and it will leave on the tiny primaries for good throttle response and once you get rolling the big secondarys will come in and start accelerating and I love the sound of the carburetor trying to eat the airfilter lol.

[@RattleTrapGarage]

I took the holly off my truck and put a used quadrajet on it that sat for 15 years and it bolted right on and fired right up and idled

[@crisandres94]

I had a q jet on my c10 that a buddy gave to me. Unfortunately the previous owner had striped the bolt that holds in the fuel filter inside the carb and it leaked everywhere after the last bit of thread holding it in the gave out. I liked it only reason I changed was because of that. However, I am super happy with my edlebrock.

[@truebetold65]

Very good video.. thanks a lot.

[@VideoAmazed]

Tyler.....do you have a video on the Adjustment of the Secondary Air Valve Lock out. The carb I'm working with is the Rochester Quardrajet 7029263 with divorced choke. I have intermittent condition with my secondary air valve hanging open about 1/4" and consequently hanging my secondary metering rods open. I've been logging gas mileages all over the place. The last one was 7.4 MPG and one time it might be 11.8 MPG or 12.4 MPG. I've checked the clearance for warpage in the secondary air valves, and also have been told that the hanger on the metering rods can get bent ? I'm not sure what the spec width is for the hanger on the secondary metering rods ? I can hold the primary door straight up and use my finger to push the secondary air valve down and most of the time it will return closed, but sometimes it will hang up ?

[@MattsRageFitGarage]

On that lawnmower, you could try adjusting the governor at the point where it goes in to the engine itself.

[@jimervin387]

Not enough volume on the sound, at least on my computer. Good info about the features of a Rochester carb, though. My '78 GMC with a Rochester 4 barrel is just hard to start without pumping the gas pedal and turning the key several times when it's cold. Does that mean replace the accelerator pump piston?

[@Warndog9]

This video does not have nearly enough views/likes. Let's fix that!

[@CarFacts81]

I love the Thermoquad too

[@AtariFTW]

I bet they would work on a lawnmower if you wanted. Don't hold your breath for the secondaries to open lol

[@hound4u937]

I put on a new mechanical fuel pump and the original engine had a mechanical fuel pump too. I never really thought to check if there is an electric fuel pump-but I seriously doubt it. The fuel tank was drained last year( just before the engine had a catastrophic failure. I replaced the engine with a fresh built 383 stroker, got it timed perfectly and then the engine started running rough. Thats when I replaced the inline fuel filter and check the Rochester carb fuel filter. The inline had the metal shavings and the Roch carb filter was clean. I followed your step by step video and cleaned out the freshly built carb ( 15 minutes of run time on the new carb). Next step is to play it safe and drain the old fuel since the carb is very clean. Im still stumped and have no idea where the metal shavings came from-very odd! Also dealing with a starter mounting hole broken so im waiting for a part to fix that issue so there wont be a welding involved. Is there a way to clean, remove the low idle thing'a ma jiggy brass tubes? Also, can you do a video about the various fuel jets? I noticed my Carb has #73 fuel jets but not to sure about the numbering system on them and what my options ( if any) are.

[@loganbyers996]

What do you think best off-road quadrajet setup would be?

[@dansmith6990]

a properly tuned one :-P

[@PhattyMo]

Heck,put a QJ on that mower! ;-)

[@gunslinger3090]

i have been running holleys since the 1970,s not 1 time had a problem with holleys leaking at the fuel bowls or accelerator pumps.

[@hound4u937]

I found metal shavings in my inline fuel filter and the Rochester filter was clean. My Rochester is freshly rebuilt. After running the new 383 stroker and setting the timing, the engine is now running rough. Im not sure where the metal shavings came from and the fuel is about a year old ( but I did you fuel stabilizer). Im guessing I need to clean out the jets. I used carb cleaner and the car showed slight improvement. Any suggestions or comments? Id love to get the 79 corvette running again.

[@TylersNeighborhoodGarage]

Is there an electric fuel pump installed?

[@SiegePerilousEsauMaltomite]

I bought a 75 c10 a few years ago and want to put one of these on there. It's got a 2jet right now but it's got issues I with which I can't deal. I have limited knowledge but I should be able to do the swap right? It isn't my DD.

[@edwalker8375]

Quadrajet is a great carb. I love Holley too. Really, quadrajet for mileage and driveability, Holley makes more power, bigger primaries, a bit less mileage. But, on the upper end power, (wide open)Rochester makes great power (750 cfm, that's a bunch).Holley though has much more tech support, and parts availability, one big plus for holley. Quadrajet is a bit hard to tune until you figure it all out. But once you get into swapping jets, metering rod springs, etc., it can be fun....

[@jesuscobos7243]

You should’ve talked about an edelbrock too

[@TylersNeighborhoodGarage]

This video isn't about edelbrocks.

[@KOSerg-vo2qb]

17058201 is a car I found cheap I'm rebuilding it right now for a olds 350 motor,you think it will work good on a 70's engine?

[@slimjim119]

I always used quadrajet I found them easy to work on

[@RetroVintageItems27]

Okay, I'm sold! Seeing what your explaining about the variable CFM's, it almost seems dumb to not use a qjet, especially if your not the greatest with engines. How's the Dart coming along?

[@TylersNeighborhoodGarage]

Slowly, but I'm continuing to gather the expensive stuff now. I need a clone.

[@austinbreen9090]

I have an 84 Camaro with the 305 H.O and was wondering what carburetor would u SuggestI put on I don't know what I have on it now

[@hurricanematthews4657]

please stay with a quad.

[@72troy455]

Get a non feedback Q-jet and a mid 70s style HEI. Mid to late 70s 350 SBC had decent Q-jets.

[@derekobidowski5784]

the Quadrajet the fuel inlets on them are in different locations the Pontiac and Oldsmobile or Cadillac engines the fuel inlet is on the front the quadrajets on small or big block chevy engines are facing the passenger side . the quadrajet on some Pontiac vehicles have a special bowl vent and uses the Pontiac air cleaner. Some quadrajets up to 1990 used electronic feedback. were mainly on the Oldsmobile 307 engine i watched a video on Davidsfarm how he put a oldsmobile quadrajet carburetor on a 305 small block chevy. on his cheviac originally a 1985 Pontiac Parisienne. as it tells me GM or Rochester had quadrajets for different GM engines as Chrysler used them too when Carter stopped making the Thermoquad for them and used Rochester on some 318-360 engines.

[@TylersNeighborhoodGarage]

Mostly correct, although Cadillac Qjets used side inlets only, and some late-70's Chevy big-blocks used front inlet carbs. Canadian vehicles normally did not require computerized engine controls, so they had standard Qjets.

[@tamapalagi]

it's ironic that chevy muscle cars got holleys and the other gm cars got qjets. the qjet cars were just as fast if not faster and drove better than the holleys.

[@72troy455]

Carb CFM ratings are theoretical, I've seen a 4779 Holley flow over 900+CFM on a 700hp 502ci Chevy. A 1050 Dominator on the same engine flowed slightly less than 1030cfm. And it picked up 25+HP over the 4150 style 750 DP. They can flow more or less than rated CFM depending on the engine they are bolted to.

[@jordanwiley4582]

All the Q-jets with the straight inlet are Buick, olds, pontiac carbs. All side inlets are either Chinese remans, or chevy.

[@TylersNeighborhoodGarage]

+Jordan Wiley Cadillac also uses side inlet and some late 70's GM HD trucks use straight-in carbs. Go figure.

[@TylersNeighborhoodGarage]

+Jordan Wiley Cadillac also uses side inlet and some late 70's GM HD trucks use straight-in carbs. Go figure.

[@TylersNeighborhoodGarage]

+Jordan Wiley Cadillac also uses side inlet and some late 70's GM HD trucks use straight-in carbs. Go figure.

[@TylersNeighborhoodGarage]

+Jordan Wiley Cadillac also uses side inlet and some late 70's GM HD trucks use straight-in carbs. Go figure.

[@christopherg9806]

Prior to watching your video, I believed all the mythology about Quadrajets (not that I'm a carb expert). I always figured that if I got a 1980's Dodge police car, I'd get rid of the Quadrajet and get an Edelbrock or Holley, but now I won't. I love that they are effectively variable CFM! Couple of questions: The late 60's Z/28 with the 302 used a Holley, I believe. Why didn't they stick with the Q-jet? Second, what made Dodge put the Q-jet on certain 318's? Not a fan of the Thermoquad, but surprised that they chose a GM product since the horsepower was pretty much the same for all 318-4bbl engines. (About 165 net.) Finally, why is the Q-jet particularly known for droning really loud, as I thought all 4-bbl carbs made an induction roar when the secondaries open up.

[@toyota-dx7ff]

why does the q jet have grind marks on the bottom in the front? and I have a q jet off a 85 gmc truck with a 305, do you know what kind that would be?

[@SouthernMechanic]

+1988toyota almost all if not all quadrajets have anti tamper plugs pressed over the idle mixture screws from the factory so you cant adjust them and the easiest way to get the plugs out is to cut the bottom of the carb right below the plugs then peck them out with a sharp punch, seeing as how old quadrajets are now its safe to say that probably 98 percent of them have been rebuilt and or adjusted so you will see those marks a lot, i may rebuild one of them on my channel if i get time

[@M4MED86]

I'm sure youve probably found out what carb you have by now,seein how your post is 3 yrs old,but just in case,it might be an M4MED quadrajet(if it's factory or oem) If you still don't know what you have,let me know

[@quickdrawmcgraw6396]

good vid! what about a carter?

[@MrJoebreezy225]

i love my quadrajunk

[@AntoineFinch]

hey tyler i have a 84 buick lesabre with a computer quadrajet ? i want to get rid of it and ecm and all the emission stuff it doesn't need emission testing in alabama, i'm tired of spending money trying to get the tps sensor and other stuff fixed? i am going to get a stall kit for my 2004-r transmission, wat else will i have to change ? distributor? etc? thanks

[@TylersNeighborhoodGarage]

Hey, how's it going? That's a 307 Olds, so you'll need a non-computer-controlled, ELECTRONIC distributor from a 1974-80 Olds small-block V8 of any kind...meaning 260, 350 or 403. Make sure it has the vacuum can and also make sure it's from one of those engines. The part number is stamped on the side of them. You'll also need a Quadrajet from the same year Olds 350-403. 260 had some that were fake Q-jets. They looked like a 4bbl but had the back air doors blanked off, making it a 2bbl. The reason you need to use an Olds carb is that the fuel line, hot air choke and cable connections are in the proper places as-is, saving you time and effort. The Olds Qjets have numbers such as 17057250/251/253 and onward substituting 8 or 9 or 0 for the fifth digit from left(model year). Remember, hot air choke, straight in fuel inlet and those numbers, otherwise it's probably a junker Chevy carb. You can find the temp sensor, oil pressure sender, distributor feed, alternator and cruise wires in the harness and remove all the rest. Don't chop wires until it's running and charging. Good luck!

[@AntoineFinch]

Thanks happy new year

[@TylersNeighborhoodGarage]

Antoine Finch You too. I forgot to mention that if you go junkyard shopping for your parts, a late-70's Oldsmobile can have a Buick, Chevrolet or Olds V8 engine in it from the factory. An Olds engine is the ONLY one that has the oil filler tube up front instead of a cap in the valve cover.

[@SOLDOZER]

You still never told us why Qjets are awesome.

[@RattleTrapGarage]

I love my quadrajet

[@Ian-of9oi]

The Holley looks older, like it was engineered in the 20’s. I doubt it was though.

[@72troy455]

Mid 70s.

[@austinbreen9090]

Also for some reason I can't get the 4-barrels to open I've rebuilt the choke and cleaned the hell out of it and still won't open.

[@jayryan7473]

The Holley in your video doesn't have externally adjustable floats. There's a metal slug on top of the bowls where the adjuster should be. Avoid those float bowls!

[@CarFacts81]

Carter made these as well.

[@realcyborgh]

good info.

[@thomasgadsby4340]

This year in less then 100 klm.ive gone through 4 holly carbs and 2 edle brocks...i have a q jet powering my mustang...always been a gm man..went for a ford mustang..now its better with gm parts.

[@grabir01]

IF you need to change jet sizes, and you will need to if you are a racer, the holley is simple to do.. The Quadrajet is not so easy...

[@72chevelle156]

racing is usually WOT to adjust that on a qjet is one screw on the secondary hanger. the primary circuit can be calculated for the engine and left alone.

[@Tigerfire75]

Why not put a Quadrajet carb on that mower? Heck put an engine on it that would come with a Quadrajet. Then you would have a killer mower.

[@TylersNeighborhoodGarage]

Austin Breen enable replies.

[@pankero1]

+WhoSaidTyler Why Quadrajet's are awesome part 1 I would like to share my reasons 3- Economy 2 - Basically 2 carburetors in one (Small primaries for economy & secondary’s for when you need to mash that pedal ) 1 - Sound, that sound, has to be the single best sounding carburetor ever made (even better than an ITB setup with Weber/Dellorto/Solex) VROOOOOOOOOOM Ps: they’re easy to rebuild and require little maintenance.

[@NoPaintGarage]

Awesome!

[@ak47popoff]

Cool

[@intromaster]

Sing

[@intromaster]

Children singing

[@SOLDOZER]

Clean your fingernails.