I’m sorry

[72c20customcamper]

But I dislike quadrajets . I had two rebuilds from two different reputable carbs shops . Truck never ran right ie engine miss and popping back through the carb so I assumed it was mechanical in nature . I parked the truck last spring as it wouldn’t idle . I decided to bring it down to my shop and start the disassembly . I tried moving the truck that wasn’t happening it was flooding and stalling . So I went and took off the Edelbrock 625 competition carb off my AMX.

Truck started right up idled well and actually drove nicely . Excuse the rubber line as it a temp to get it on the trailer . I’m going to add some hardline and a filter

[72c20customcamper]

I didn’t want to run it to long as the oil was gas saturated so tomorrow I’ll change it and go from there

[Casper42]

I never had any issues with the Quadrajet, particularly about what you experienced. I only heard problems with Edelbrock and Holly.

[body bolt]

Same story here. I would like to use my original Quadrajet but it's nice not to have the truck die at stop lights.

['68OrangeSunshine]

And I've Never had an issue with a Carter AFB or Edelbrock Performer.
Can't say that about Q-Junk.

[SRU1436]

The stock Quadrajet on my 72 C10 works fantastic. The aftermarket Holley works fantastic on my chevelle. I must’ve lucked out.

[Palf70Step]

I have always had better luck with the old Carter or Edelbrock carbs. Never had any luck with the QJets in the past 50+ years. I like the Holleys for racing, they seem to tweak better in that realm. For daily use, I like the Edelbrocks though. A lot I guess is just what we get familiar with or have luck with.

[1970cstblazer]

The Q-Jet is as sophisticated as it gets for a carb. They work well IF you address some widely known sore spots, such as leaky lower casting plugs, worn throttle shaft bushings, warped air horns, and inadequate idle fuel calibration for any engine that is modified from stock.

I run them on ALL of my vintage GM vehicles, and they work very well in all weather, and engine conditions. They manage to get good fuel economy if you can resist the temptation of opening it up.

[72c20customcamper]

Sophisticated = complicated .

Now I’ve had a qjet on my 85 that runs well 99% of the time . It’s just that the average guy with limited knowledge can tune an AFB which is probably one of the simplest carbs out there . Same for a Holley side note my Chevelle came from GM with a Holley carb and the manifold even has Holley embossed on it

[1970cstblazer]

To me, the Q-Jet is the easiest carb to rebuild. Caveat is that I have rebuilt over 100 of them over the years, so I know the nuances around them. I have had a couple of them that were difficult, but I attribute that to others monkeying around with them and replacing parts from other carbs because they look the same on the outside.

[MARKDTN]

I have never had luck building a Quadrabog myself, but I have had some built by good shops that were outstanding out of the box. Have had stock ones that were great too. "The Carb Shop" in Ontario CA used to be the go-to but I think the owner died and it is not what it once was. For a while I was buying Holley rebuilt Q-jets from Autozone but I believe they are not done in the USA anymore and quality has slipped. Ethanol fuel is also hard on them I understand.

I have had good luck with Holley too. Have built many of them successfully. Have 1 left that is on a boat.

I have had no luck with Edelbrock carbs at all.

But all in all I am done with carbs except the boat, weedwhacker, and a lawn mower (and my flathead V8 2N tractor but the carb is never right on it). I love fuel injection conversions. Better starting, mileage, power. I have 2 Tuned-Port conversions running and could not be happier with them.

[Troy Sr]

I've never had any problems with a Quadrajet, I've rebuilt many of them and had good luck with them!! I only problem I've had with one was when I was drag racing my '55 Belair it would run out of fuel at about 3/4 track and stumble!!

[Rust_never_sleeps]

Mine runs great, but it's all original, so completely matched to this motor, which is a common failing of transplanted Qjets.
My neighbor, who's built more motors and cars than I ever will, gave up on his and swapped his for an AFB.
YMMV

[72c20customcamper]

Originally Posted by Rust_never_sleeps

Mine runs great, but it's all original, so completely matched to this motor, which is a common failing of transplanted Qjets.
My neighbor, who's built more motors and cars than I ever will, gave up on his and swapped his for an AFB.
YMMV

The numbers on the carb I just took off match what should have been on my engine from new . Is it the original who knows but it’s period and correct for a 327

[chevmn]

Repair a Q-Jet and it will do as good as anything out there (probably better). I remember one instance where I was ready to give up on one, and took to someone that knew the common issues, and the problem I was fighting was simply a heavy (fuel soaked fiber) float. He advised always replace with a brass float and that problem is gone for good. The carb was running fine till many years later when I traded the truck. Couple years ago I had one that I was fighting, and discovered a crack in the main body (leaking badly). As others indicated, worn primary shaft, leaky well plugs, and sunk (heavy) float. I just rebuilt one that had ran propane, and even though the truck only had 62,000 miles, the propane gave no lubrication to the throttle shafts, and was worn out. Drill and bushing fixed that issue.

[Rust_never_sleeps]

Originally Posted by 72c20customcamper

The numbers on the carb I just took off match what should have been on my engine from new . Is it the original who knows but it’s period and correct for a 327

yeah, it's a common problem, but by no means the only one ;-)
Having the right parts won't guarantee success, but having the wrong ones will guarantee failure ;-)

['68OrangeSunshine]

I know some people swear by Quadrajets, especially if they're OEM on a numbers-matching engine.
When I bought my '71 Jimmy in 1995, the PO swore it was a 327. He said it once had a nice hi-perf 350, but -- cost of living in LA -- the truck had been stolen, and the engine was gone when the body was recovered. It was really a 307 Mexican Mr. Goodwrench.
When it didn't pass AZ emissions, I took the Q-Jet that was on it into Checker Auto and traded it in on a re-man Q-Jet off their shelf. That one sucked worse. I didn't know that they were tailor-tuned for each specific vehicle. [Not so sure that the first one was anyway...]
A gearhead buddy gave me a Holley 4150 Double Pumper 780 CFM, which was way overcarburated. I proceeded down Folly Lane by trying a top off with 105 Octane race gas. On my way to the Emissions test, the engine made some funny noises and blew up. After testing, we concluded that valves #6 and #7 had sucked in, and smashed the porcelain spark plug tips. One on each side.
So I parked the GMC and it lay fallow for about 2 years.

I had a '67 K/10 Suburban w/454 and a Carter AFB, and a '68 C/10 Stepside w/292 and Holley 390 CFM. In late 1998, the Sub had an engine fire, and it was time to resurrect the Jimmy with a new Mr. Goodwrench 350. The Federal Mogul Competition Series Carter AFB was the most economical choice, and I liked the AFB that had been on the 454 [before the fire]. I was leary of Q-Jets at this point.

I ran a Holley 4160 R8007 390 CFM 4Bbl on an Offy intake on the 292 in my '68 C/10 Stepside from 1978 to 2002. After 250,000 miles the L6 now needed 50 weight oil and was blowing smoke rings after every stoplight. Time to rebuild. We completed that engine swap in 2005. I rebuilt the Holley. When the 292 was only running on 4 cylinders [unknown to me until we put it on a Sun scope] -- I added a 50CC acellerator pump. It ran OK for the 500 mile engine break-in, but right after, I had a backfire, killing the 8.5'' Hg Power Valve. When we tried to set it up again, it would not hold. A warped base plate was suspected.
I had always needed adult supervision when doing anything on a Holley.
Instead of buying a lot of Holley parts, I looked for another Carter AFB at 400 CFM. No such animal. Fed Mogul had dropped the Carter AFB line, ceding the field to Edelbrock.

Quadrajet on an L6? Not in the US market. No way Jose. Ironic, because in Brazil where they run 100% cane alcohol 1050 CFM Q-Jets on 292 [4.8L] L6s were common. But I had no Brazilian connection.

So Edsel-brock was the only game in town. As a Carter fan, I thought Edelbrocks were the same thing, but $50 to 100 bucks more because of the shiny finish. Maybe, if they gave me a red satin Edelbrock tour jacket, and a big red decal for my high school locker, I could sit at the cool kids' table at lunch. But I was a long time out of high school. Truly, they were [are] made by Weber in the same plant. Anyway, I got a 500 CFM 1404 Performer for my 292. They don't sell a 400 CFM AFB-Clone. WCFBs had 400 CFM models, but are unavailable.
Very happy with my Edl-1404 on my 292.

[72c20customcamper]

My Chevelle has had a Holley carb on it since new . The original manifold even has Holley embossed on it. I have the original motor on a stand in my dads barn . It’s latest rendition has a 770 street avenger tuned to the motor on the dyno

[Steeveedee]

My original-to-the-truck QJet works just fine. I've rebuilt it ~four times in the last 40 years, three times while it belonged to my FiL. YMMV.

[MikeB]

Originally Posted by Steeveedee

My original-to-the-truck QJet works just fine. I've rebuilt it ~four times in the last 40 years, three times while it belonged to my FiL. YMMV.

That is really cool!

[Rust_never_sleeps]

This being a hobby, avoiding anything you don't enjoy doing is totally legit.
If you don't enjoy tinkering with balky carbs, and you found one that just works, run that until she don't run no more.

[RichardJ]

>>OK, this thread has gone over the top for weird...<<


And, that is only half the fun. No one screamed out that the sky was falling. No one cried foul. No none insisted that the engine couldn't even be running much less than be running better than a Q-jet.

He has committed the offensive sin of using the ported vacuum port. Oh, the horror of it all.

This carb doesn't even appear to have the manifold vacuum port drilled.

Surely, a sin against the gear-head gods has been committed.

How's that for redirected topic?

[MikeB]

If someone hasn't mentioned it yet, the carb in the OP's picture is a Carter AFB. Each of those carbs was calibrated for a specific engine, in this case maybe an AMX 390.

Edelbrock sort of copied it and has probably sold at least tens of thousands over the years. They are rated at 500, 600, and 750CFM and have the fuel inlet on the passenger's side. Also, some of the AFBs had 3-step metering rods, whereas the Edelbrocks are 2-step.

I call TMI on myself!

[72c20customcamper]

Originally Posted by MikeB

If someone hasn't mentioned it yet, the carb in the OP's picture is a Carter AFB. Each of those carbs was calibrated for a specific engine, in this case maybe an AMX 390.

Edelbrock sort of copied it and has probably sold at least tens of thousands over the years. They are rated at 500, 600, and 750CFM and have the fuel inlet on the passenger's side. Also, some of the AFBs had 3-step metering rods, whereas the Edelbrocks are 2-step.

I call TMI on myself!

This is a 4759s made by Carter . 500 cfm made for the AMX with dual 4bbl setup . I got them and the manifold when my uncle was an AMC dealer

Edelbrock bought the rights to these and they were made along side of the Carter AFB on the same Webber carb line .So the really didn’t copy it

[RichardJ]

>>some of the AFBs had 3-step metering rods,<<

Actually, only the Carter AVS carbs used the 3-step rods. That includes the newer Edelbrock AVS carbs that are also the 2-step rod design.

>>Each of those carbs was calibrated for a specific engine,<<

Not as critical as some might assume. I have a 1970 383 Mopar Carter AVS on my 292 six and it works just fine with no jet changes. I did change the springs on the vacuum pistons above the rods. Its been on there about 17 years.