This video was admittedly a bit rushed, so there are a few rough edits and probably too much talking. A lot of info in here, but still missed talking about some things like air valve tension or a real explanation of APT adjustment. Also the voiceover toward the end sounds like it has been slowed down, that is just how tired I was when recording it. Hopefully this is still an enjoyable episode!

I had a '76 Caddy that someone had removed the filter from the carb. It took approximately 4 eternities to cold start every day until I figured out the problem... Absolutely run that filter.

I was a GM technician for 25 years, but its been 12 years since I worked in a shop. Your videos sure takes me back! Your energy, enthusiasm, and determination inspires me too. Keep the videos coming! BTW, I just bought a 1993 Sonoma 4x4 project truck.

For those of you wondering, the APT stands for Adjustable Part Throttle. The power piston (spring assembly that holds the primary metering rods) has a little metal tab on it that rides on the APT screw. The power piston is pulled downwards against spring pressure (spring inside the piston) when vacuum is high at idle and part throttle (cruise). However, the APT only effects cruise A/F ratio. Qjet has Idle, part throttle, and WOT fuel systems. Idle is done with idle screws, of course. Part throttle/cruise is done with APT, WOT is with different secondary rods (and hangars), among other things. You can change primary jets too, but with the power piston being adjustable and there being many many different width primary rods available, you almost never have to. The APT screw determines how far down in the jets the metering rods sit. Screw it in (down), it's leaner at part throttle as the rods are further in the jets, letting less fuel by. Raise it up, and it's richer. If your qjet car has a noticable dead spot at cruising rpm (1200-1800ishrpm), this is the adjustment you need to make. It's not a bog, it's a dead spot. Like you slowly roll into it and it feels like nothing is happening. Something like a baaaaaaaaaAAAHHH. You almost cant feel it unless you are looking for it. Having an A/F gauge really helps in tuning the APT, and carburetors as a whole, not just a quadrajet. Jegs (among others) sells a kit to make the APT screw on any M4MC (75-80 non computer carb) externally accesable. #561-201495 They also sell a bracket (again, among other places, shop around) that is basically a copy of the stock GM bracket used on v8 qjet cars with a Th200c (three speed auto, known as the "200 Metric"), Th200r4, or a Th700r4 transmission with a TV cable. #890-376700 Don't listen to the reviews, they're retarded. It's clearly a qjet bracket, no shit it won't fit an edelbrock.

I went from a 350cfm Holley 2bbl to the Holley 2bbl sniper tbi system on my Ford 300 in my 81 Bronco, really smoothed everything out although the carb wasnt really an issue, But I hated my bowl losing fuel whenever I was offroading up a steep rocky incline.

The Quadrajet is both versatile in fuel economy being a spread bore, and performance due to its large secondaries which make it capable of 750CFM, and 800CFM in later models. Good choice. Actually, the vacuum break for the secondaries is necessary. It holds the doors closed until the vacuum drops enough to warrant the secondary valves opening. Without it they will open lifting the secondary metering rods causing excess fuel being dumped into the engine.

A lot of old timers called this carb Quadra junk, it takes a real competent guy to tweak them out IMHO

Replace the choke pull off really helps warming up the engine by giving the engine more air during warm up

Love your PTSD about spending 50 bucks on the ideal specific dream carb that you can't find anywhere else. Hahaha :P

I call shenanigans on the engine starting right up. It would have taken me at least a month to get it to fire and another week to get it to actually come anywhere near a smooth idle, lol. Good job and thanks for the vids!

I love Quadra jet carbs when they run right. They have great throttle response and the sound they make when the secondaries kick in is awesome. I have an edelbrock and could never get it to run just right.

You are one smart dude! Love watching your videos. I really learn a lot. Thank Man!

This has been a great build! (I mean the entire series) Not what one would expect. And not exactly the way we did things in the 90's. Very illuminating, and eye-opening throoghout this build. Thanx very much! I look forward to marathon watching another build from your archives! :D

You had a square-bore Edelbrock AFB carb on a spread-bore manifold, which was designed for a Q-Jet. Your Q-jet should be more effective just being on the proper manifold, without an adapter. Note that an Edelbrock/ Carter AVS (air valve secondaries) carb is similar in operation to the Q-jet secondaries. They were found on Mopar 340 engines mostly, and worked great. Your V8 S10 series is really well-done! I had a non-computer controlled T4 1984 S10 Blazer I managed to get 225 HP out of: .060 milled /ported heads, Crane cam/springs, Bored .030, Melling pump, recurved distributor...

I admire the amount of patience you have with vehicles

The 454 in my old Suburban had one of those. It worked pretty well after I removed the plugs, fixed the leaks and tweaked it.

I love this vehicle. So great that you shared these videos

Love these videos, better than TV by a long shot.

As usual, very well done vid and great entertainment. Thanks.

i just stumbled upon this series and channel about a month ago, and at first i didn't really care for it, but, after watching the series from the beginning i have actually started to appreciate his channel. i even subscribed to it and plan on watching the other series. i appreciate how he goes through everything he did and doesn't skip over the small parts, as well as also including fluids and stuff that he uses. the dry humor helps the video be a little more enjoyable overall. Keep it up man, your doing great!

nice timing on this, the Qjet on my 71 Cutlass just started spitting gas out the top. looks like I'll be pulling it apart soon. great video BTW. I can tell you did your research.

Love the sound of a 4bbl opening at full throttle. Wha whoa

I know this is a little late but in the pursuit of fuel economy, every MPG helps. If you can get a huge 5 mpg improvement. going from 11 mpg, over the corse of a 10000 miles you'll have bought 2163 dollars in gas over here 16 mpg or 1475 dollars of gas. its why IMO its worth it to buy nice fuel economy tires on your everyday driver even if on the surface they cost more and spending the extra dollar at first to squeeze a couple more MPG out of a your car. :)

I like your Blazer videos. I always wanted to swap a V8 into an S10. I'm surprised you're not getting better mileage. I built a hot 350 for my '50 Chevy and got 21 MPG on the highway. I've since swapped the 350 for a 454 and still get 17 MPG on the highway. Granted, my car is not 4 wheel drive and is much lighter than the Blazer, but I thought you should be getting at least 15 MPG. You're close. Keep plugging away. I'm sure you will achieve the desired MPG your going for.

Running an original GM air cleaner assembly with a fresh air duct and a temp-controlled hot air exhaust manifold duct, designed by GM engineers back in the day, works really well on these engines both in hot and cold weather.

8:51 I thought the term you were looking for was 'jig', but the Googlé cautioned to not confuse a 'jig' with a 'fixture'; the latter holds a workpiece in place, the former helps guide tools for reproducible operations on work.

keep up the videos I like how informative they are!! and entertaining

Just watched your whole series on the blazer. Really liked it. Starting the trans am next.

Id like to strongly suggest getting a gallon of carb dip and an air comoressor. Without these two things its nearly impossibly to confidently say a carb is truly clean. This can lead to many frustrating days trying to fight a tune when theres actually a passage blocked. Im saying this from years of experience. They both cost money but with the amount of carb work you do its money well spent.

Good thinking testing the hood for clearance. I can't tell you how many times I changed that stud on a car... slammed the hood... and then cursed the little dent it left.

Love the sound a properly tuned qjet makes at wot!!

I like your attention to detail. I'm a Quadrajet fan, personally. I prefer Holleys but I'm a poor boy. I always deburr the butterflies and polish internals. They're good carbs when paid some minor attention and like you said, they're good for offroad. Edit: running an 800cfm Qjet without the internal filter will cause issues, in my experience. It's more of a regulatory device in that way. I also run curve kits in my HEI distributors and eliminate the vaccum advance. It's smoother and I really hate a lot of vaccum lines 😊 I always check the idle air valve because sometimes I want it and usually I don't but it seems like everyone just bores it out regardless.

I loved my quadrajet in my 256 Holden Red engine! Amazing

Nice work

thanks very helpful video im currently getting a vortec 350 to drop in my s10 i got the intake and quadrajet carb today so she is almost ready

amazing videos, keep it up!

Quadrajets are good for economy, but performance wise some have given it the name Quadrajunk!

you explained everything so well damn.

IIRC, the idle bypass circuits, including the adjustment screws, are all on the throttle plate, so the top part of the carb and all the tricky internals can stay mostly assembled for access.

Thumbs up for your bracket!

if you were to weld in a bung in the exhaust and hook up an O2 sensor, you could tune it to the right setting and KNOW you have the best settings.

Those carbs are super difficult to get right. Good job!

I would get those other parts. The guys who designed it knew what they where doing so I think they are good to have.

Sorry but I sit here chuckling at all you went thru to get to 14 MPG. Did the same with a freebie Holley 600 and tied secondaries shut making it a 300 and went from 12 to 18 MPG on a slightly above stock 350 running 9.5 compression, a stock 350HP/327CI cam (a $300 engine) and a turbo 350 in a 85 Monte Carlo. Granted the 2:71 rear gears helped a bit. Not a stop light burner but often broke NY's 65MPH speed limit in low. I believe GM made a 500 CFM 2 bbl (center carb of a tri-power). I still am enjoying your videos and look forward to watching your other series as this has been a fun learning ride. Thank You for all your work!!!

13:01 %$*^. When I rebuilt my first Qjet back in the early 90s, I didn't have any reference material to consult about how to go about getting that rod assembly back in place with the gasket in the way, and thought I must have surely missed some trick or technique for going about it. While I haven't yet finished watching the video to see if your Qjet squirted fuel out between the housing as mine did after I got it back together: The rebuild kit's fuzzy diagram had numbers next to each of the dozenish housing bolts, with no explanation that they signified the order they were to be tightened to prevent fuel squirting out the sides.

Why is it so hard? That's what she said! Shadap Michael

NICE! a spread bore carb on a spread bore manifold

I just bought a C10 with a 350 and this exact carb and all the parts needed on it. It was on the floor of the cab.

My sister had a S-10 Blazer! I got the opportunity to drive it of a cliff, obviously I jumped out!

Thanks for making a video

Looks like you got a pretty good core. The later ones in the 80s had electronic controls.

14 mpg is about all those blazers got with a TBI 4.3

New sub for the S10 content 👍🇺🇸👍😎

Quadrajets are also good for power and performance.

some marine quadrajet in older moters have the right linkages setups

You should play around with efi.

She runs well.

Cool video. Doesn't matter if the bird sings

i just get a piece of metal fuel line and squeeze it with pliers to adjust my idle mixture screws

Just no winning with that truck, thats why its fun to watch!

You need a wideband o² sensor gauge to tune it correctly once for all. Buying carbs and parts to adapt those will make you spend more at the end,for a rough ,or bad result. You can find one new for 150 $ in your country,from the AEM manufacturer,wich is a good brand,and cheaper used. I'm pretty sure you can have one in a junkyard on a honda civic lol

it's a chevy that's why it sux and sux fuel...lolz....I was a chevy guy when I was young like you...but I realized as I got older and wiser...like 50yo...ford products are supreme...yep...but I still love yr video...you are very talented and extremely knowledgeable....I would love to have yr mad skilz...btw...my truck of choice is either an old 7.3 powerstroke my work truck but my personal truck is a 04 dodge Cummins....it get 22 around town and 30mpg on the highway...at it's a duelie 9,000lbs...cant beat that....

Please fix your Fender and bumper

Quadrajet isn't just good for fuel economy but also good performance too.

When the series going to continue?!? Been two months!! Love these series!!

hmm did you block off the passage in the choke housing? manual choke carbs have a hole in one of the 3 legs on the choke housing. the choke coil also had a gasket on the manual choke carbs. since you changed to auto choke, there is no gasket between the coil and housing so it can ground the circuit through there. You must plug the hole that goes from the choke housing into the carburetor body

he visto tus vídeos y creo que eres buen mecánico pero creó que esa camioneta esta salada. mejor llevala al jonke más cercano y te vas a evitar muchos mas problemas. pero tu lo as echo bien

You got some stuff right about the carb and some stuff wrong. Vacuum break for the secondaries is done by the front diaphram, with adjustments done to the spring on the other side, which go hand in hand with the vacuum break. You don't need to change jets because they are adjustable jets done by the APT. Power piston spring can be left out till cruising speed adjustments and idle adjustments are done, then you can tune in the power piston. Your distributor vacuum line is wrong, should not be sucking at idle, starts sucking off idle to cruise speed, and is the lower right port on front in the middle section body. Your idle is high because when you start the engine, the timing sky rockets with the port you are using, use a gauge to confirm vacuum port for distributor. Some carbs are different to where the ports are all the same, as they all suck on idle, which is the wrong base plate for what you want. Maybe buy a book on the carb from Summit, they are great and is way better then doing research from You Tube. I built my Qjet from 4 different carbs just to get it to do what you are trying to do. You need to know this carb to get it to do what you want it to do. And ignition timing goes hand in hand with these carbs if you want fuel economy. You would have been better off staying with the Edelbrock carb, they are way easier to do this.

you can tap the air bypass and use a fitting to reduce inlet diameter?

Take it from a gm tech who had to work on those e4me carbs at the height of their popularity, even when they were new, they were garbage and a real pita to tune and make work. Get a older car where the million miles of vacuum lines were cracked and leaking, forget about them working. Many times I'd hit the salvage yard and swap to the vacuum advance hei distributor and quadajet like this one

Did you hit a deer? Was this explained in a previous episode I may have missed? Hope you can fix that one day. Keep up the great work man.

try to get a qjet out of 80-85 305 caprice would give you the best economy. and if i were you i would get a ready rebuild carb from ebay for 200-300$ and you will forget about playing with it for 5 years and more

Hey fuzzy dice projects the 350 still running strong? Interesting videos! I'm currently rebiulding a 1970 chevy 350 that I'm probably going to put in my 98 chevy s10 4x4.

In the early 70s they had a funny quadrajet, the primary side was normal but the secondary was completely un-machined.

Edelbrocks are the Southwestern Airlines of the carburetor world.

Even with 2mph jump it will pay for itself. More than likely your ring and pinion is the biggest drain on the fuel. I'm thinking the Firebird had maybe 331s and Blazer is 373 or 411s? Great tutorial on the Q.

Just my two cents worth man: may be time to get a Holley carb and be done. I say that but I enjoy your videos too much to actually want you to do that....so yeah😂😂

That’s great and all but I’d like to see you put new belts on a riding mower.

hey, do you know any way to replace the return tension spring for the secondaries in a quadrajet? this spring isn't included in any rebuilt kit one found - do you know?

Go with a 500 cfm Summit for mileage. It will pay for itself within a year.

When will u fix the front end from the ice crash?

Think it’s time for a fuel injection set up

I'm trying to replace an old Solex carby with a Weber but I think I'm a bit out of my depth. I can buy a new Weber 32/36 DGV new for a couple hundred (can't find any suitable used ones at all) but can't figure out what else I need (cable adapters, hoses etc). Really want to get my car running again so I'm a bit frustrated I can't figure it out.

Fuzzy, will you be my Dad?

Does someone know why he hasn't even considered shifting to fuel injection? Is it only because of cost or is it just not possible?

The only bad thing and it's downfall for the qjet is the brass bushings the throttle blade bars use will wear rather quickly and make it impossible to adjust idle air and fuel mix and not for a novice carb builder because they are rather complicated to rebuild but for expert builders that carb is a beautiful beast and I have four rebuilt ones ready for my drag s10

I’m not a fan of quadranets I’m a Holley man but the one I had was old and it ran the motor like shit if I would have rebuilt it it probably would have ran fine and done it’s job I’m not hating great video but I wanted a performance carb for a performance motor I understand why u did it and I probably should have because my truck only gets about 9 miles to the gallon I’m getting tired of it and bout ready to sell the damm thing because it’s a fucking gas hog debating on just putting a stock 350 in it with a quadrajet don’t know yet but I’m thinking lol great video dude I subbed and love your videos great video content!🤤🥩🥴

Speaking of hot, does the engine run hot at all?

You mean ( kick down cable ) also 50 US for a carby that's cheap as .here in Australia that carby would be over 250 second hand eazy not too mention 600 plus new

What do you think you could accomplish with this truck? 17 or 18 tops?

I had a Quadrabog on my 70 Chevelle and it was low on performance and gas mileage.

Are you gonna fix the ac for the summer

Maybe smaller tires could improve you mpg

Hey, just a question out of sheer curiosity but. I have a 350 aswell, more like a 355 after the work that's been done to it. Would you think the Holley 1850-2 is a reasonable choice, or should I try out the quadrajet?

Have you thought about putting a 5 or 6 Speed in it

How did you hook up the cable for your 4x4 cause I’m done with the vacuum operated shit on my 87 s10 blazer

Did you mess with the fast idle at all? I didn't see it in the video. that could be the cause of the high idle rather than the idle bypass mod.

oh mai

What's your ign. timing at cruise? You want 45-50 degrees for better mpg.

This car would be fine to tune on the dyno