[Cliff R]

Finally had a moment to tell a story, and I love stories especially when they relate to what we are doing with our vehicles these days.

It's not about a Pontiac engine, but everything relates to what many of us will face when selecting components for our engines. It's going to be a lengthy read, but worth the time.

A very good friend of mine is an arborist and has his own company that does tree removal. He purchased a very nice mid 1980's Chevy 1 ton dump truck to pull his wood chipper and haul equipment and employees to and from jobs.

About a year ago he spun a bearing in the original 350 SBC 2bbl engine. He opted to trade the new engine and install for some tree work (barter system) with a local engine builder and SBC "guru".

The builder installed a "rebuilt" 406 SBC engine and my friend mentioned that I did carburetor work, so the "builder" called me asking if I would build a carb for this new engine. He told me that it "required" at least 750cfm, double pumper would be a bonus. I told him that I only did Quadrajets and he immediately blurted out that he wouldn't have one of those POS carburetor on anything he built.

That was good news for me and kept us "out of the equation" as I've been around this sort of thing long enough to know that guys like that are more often than not "hacks" anyhow and not professionals. My suspicions were confirmed when he told me that he had installed a "high performance" Comp Cam, double hump heads, and Edelbrock Torker II intake, which are NOT well suited to this sort of application right to start with that relies on smooth idle, strong power off idle and all the power in the lower rpm range.

Anyhow, about a few weeks later my friend calls me and wants to bring the truck up because it has a "shake" in it. I asked if the flywheel was replaced (400's are externally balanced) and he said no, so back to the "guru" it goes.

Not even two weeks later my friend calls and asks me if I would look at the new engine as it just isn't running well, consuming TONS of fuel, and refuses to idle down consistently. He is also having cold start issues with it.

So I take a look, adjust the choke, retard the timing about 20 degrees, and sent it down the road. I wished I hadn't touched it, fearing that I had now "married" this job.

My instincts were correct, and in the past 10 months or so two weeks haven't went by that my friend hasn't called me to rescue him off a job, or stopped by with his truck for me to take a look at it for not running well.

So, we have the background on the project, now we'll get down to the meat and potatoes. The brand spanking new Holley Street Avenger 750cfm DP electric choke carb is absolutely the biggest POS I've ever had the privilege of working with. The electric choke set-up is HOPELESS, and despite all efforts just flat refuses to work well. It doesn't go two weeks without flooding profusely out the vents on one end or the other. Usually a good "whack" with a big screwdriver handle and pinching off the fuel line corrects that issue. I suppose part of the trouble is the braided fuel line and clear glass in line filter set-up. Probably isn't helping that the fuel line down at the pump was cut off with a hack saw and chewed up the rubber some on the fuel line.

Even so I've installed numerous genuine Holley N/S assemblies and replace the floats in both bowls as well just for good measure. I've had to remove the metering blocks more times that I can count as well to blow things out, and I suspect the carb is de-laminating and small particles of material are moving thru it adding to it's already horrible running issues.

The vehicle requires 20 dollars worth of fuel for a 10 mile trip to and from a job, so it's a dollar a mile and no amount of jetting in either direction made a dent in that deal....FWIW.

We also traced down the Summit HEI distributor as a contributor to the piss-poor inconsistent idle characteristics the engine has. So that part of the equation isn't helping things out either. At this point folks may be wondering why I just don't build a carb for it and replace the HEI and be done with it.

Well, two reasons why I shied away from that deal is that the engine is NOT my doing, and if I put much better parts on it, and it drops a valve or throws a rod, the local "guru" will most likely use that as a disclaimer and not fix it.

So basically I'm just keeping it going without getting deeply involved in it.

Well last week my friend called me up, the truck was broken down again on a job near here, and he told me that he had a major falling out with the engine builder and was DONE with him.

So I had it flat towed so we could work on it. We replaced the Holley Street Avenger with a stone stock 1973 Q-jet from an Oldsmobile 455 motor home engine. Nothing fancy done to it anyplace, just a complete/correct rebuild with modern components. We did this because those units were not emission calibrated and set up for heavy duty/towing use.

Good choice as it roared to life instantly and ran better everyplace than the new Holley it replaced. We still had a minor idle issue with it as the Summit HEI distributor was adding is some timing clear down at 650rpm's and you had to lower the speed screw to get it to "settle down". Even so, when the idle speed was re-set at 650 rpms and the engine revved up, it would NOT return to idle as the weights/springs were hanging up and not allowing the timing to return to the base setting (sound familiar).

We opted to do a quick-fix there and replace the POS springs in the Summit HEI with GM parts, which instantly corrected any and all idle issues with the engine. It now idles nicely at 650rpm's and doesn't "run-on" any more when shut down like it did with the previous carb.

Now here's the best part. We put 5 gallons of fuel in the empty tank prior to the carb install and run-in. Then we drove the truck all over the place and the gauge barely moved. I even took the truck out for another run before we had the owner pick it up just to do a cold start and see how it acted thru warm up, etc. Even with considerable idle time, tuning, and several trips to check things out it isn't using half the fuel it was with the previous arrangement!

So lessons learned once again for me as I have avoided any of these type of parts for decades now, knowing full well they just aren't that great and not getting any better.

In closing I'd add here that these are just my recent direct involvement with a specific application. I don't want or need any more work in the shop, so no intentions whatsoever to steer any work in my direction. Just pointing out that this stuff isn't getting any better, and if you buy these type of parts and have good luck with them, I'm happy for you.......Cliff

[steve25]

Incredible!
He is lucky his new rings are not washed out!
Yeah , those Q-jets man ! Garbage, that must be why GM used millions of them and even Ford used them because they wanted buyers to come back day and night for warranty work!

[pfilean]

Everyone should have friends like you.

[Tom Vaught]

Not all Rochester Carbs (Q-Jets specifically) are POS carbs. Very few are (unless they were butchered up by rebuilders making a fast buck).
Same deal for Holley Carbs (The Avenger is near the bottom of the list of Holley notable carbs but Holley was sold off and did go bankrupt several times which should tell you something about the management in charge after the mid 80s. It is a marketing game these days not a proper carb engineering game. Jon Hargrove can tell stories about Carter AFB carbs (from the good guys and from the current builder of the carbs).

But Cliff, everyone has their issues occasionally. A Holley instruction guide that tells you that you can open up the idle mixture screws 2.5 turns on a 4 corner idle carb says a lot.

Tom V.

[glhs#116]

Gotta admit, I think really really hard before replacing a factory part with anything new/aftermarket. And if I can source a good used part I generally prefer it to a new reproduced. It's simple, really. The factory had the resources and incentive to make something suitable and durable. The small aftermarket companies have neither. Sometimes you need to go aftermarket because they offer things the factory never did. But, like I said, I think long and hard about it.

Sam

[Cliff R]

Tom, good points and I'd add here that I am NOT a Holley basher, and actually have excellent success with them and have dating clear back to the mid-1970's when I first started getting involved with this hobby.

We still build and use Holley carbs for some applications, and do a few restorations for them here and there, but I shy away from anything they have made in recent years. This thread is certainly not meant to "bash" Holley products as a whole, just pointing out issues with a currently produced product and the "saga" the owner has went thru with it.

Of course anyone on the outside looking in can clearly see that the engine involved here is not well suited to the task at hand, and few of the components are well matched, etc. That doesn't take away from the fact that two of the most important parts used on it were NOT making the grade, and both were purchased brand new and installed right out of the box. Of course anyone doing the same thing would certainly expect them to work correctly after spending their hard earned cash on them, which is clearly not was happened here.

I'm also glad that I was not involved with this project at any level other than being tasked with keeping it moving for the first year of it's life. On purpose I did NOT change out those parts until the original builder/guru was no longer associated with it. The WORST thing you can do in this business, is to put a hand in someone else's botched up job when you know fully well it's doomed. If you choose to get involved rest assured you will quickly be getting ALL the blame for it not working well, and blamed for any and all issues that occur after you touched it.......Cliff

[68 Firebird]

My firebird is in the body shop getting stripped and repainted.
Yeah the body guys joked about the Quadrabog. And they run this and that.

Your gonna do all this work to this car and then run a Q-Jet? YUP!!

I am a street cruiser only and enjoy the performance mine has, as well as reliability.
A few months have gone by now, and The lead guy comments how mine always fires right up and doesn't require new plugs every few months.(I had to show him how my elec choke operated when it first arrived!!)

He looked even more shocked when I said she averages 16 MPG and has hit 18MPG on longer highway cruises!

Gerry

[1968GTO421]

Originally Posted by 68 Firebird

My firebird is in the body shop getting stripped and repainted.
Yeah the body guys joked about the Quadrabog. And they run this and that.

Your gonna do all this work to this car and then run a Q-Jet? YUP!!

I am a street cruiser only and enjoy the performance mine has, as well as reliability.
A few months have gone by now, and The lead guy comments how mine always fires right up and doesn't require new plugs every few months.(I had to show him how my elec choke operated when it first arrived!!)

He looked even more shocked when I said she averages 16 MPG and has hit 18MPG on longer highway cruises!

Gerry

So true. Also, it also helps to use an original Pontiac distributor (points or HEI) that is properly rebuilt and curved correctly for the individual engine.

[77 TRASHCAN]

Originally Posted by pfilean

Everyone should have friends like you.

Yeah, Cliff must have the nicest looking trees in Ohio!!!

I've been to 2 swap meets this month. My buddy and I walked up to a table full of carbs. I pointed to a refurbished Avenger, told him to NEVER have anything to do with one of those....He has a 3310 on his 429 Ford, knows how to work on it...

[carbking]

Lots of items have teething issues.

The Q-Jet arrived in 1965, and about 7 nano-seconds after the first one hit a Chevy dealership it EARNED the nickname quadrajunk! By 1968, ALL of the major issues had been corrected. The animosity toward the Q-Jet today is mostly "parroted" by individuals who have never tried one. The internal dashpot, umbrella fuel valves, and of course, the well known well plugs were issues.

With the Carter AFB (1957), the issue was the placement of the pump check valve (changed in 1958) and the secondary diaphragm (because of FoMoCo's insistence). After a couple of years, Carter told Ford NO MORE! And went to the much superior weighted air valve (used on most AFB's other than Ford, and a few Chrysler).

The Holley 4150 was also introduced in 1957. I can well remember mechanics groaning, and stating "you have a (cough, cough) Holley on your car! They would actually fake a cough with their speech!!! My own personal experience with the 4150 was worse! Three cars I bought new had an underhood fire because of a leaky Holley within the first 9000 miles (one with less than 3000)!

The Holley 4000 was MUCH more reliable than the first 4150's. Today the "haystack Holley" has a bad rep because of internet parrots. I still like the design, got over 200k trouble-free miles from one I built at age 14. If a 14 year old can get that result, the design cannot be that bad.

The first issue of the Carter TQ had press-in main jets. This was a disaster. I once asked the design engineers WHY. The answer - the advertising yokels were agog over the Holley press-in fuel valves. The press-in jets were replaced by screw-in jets after the first production run!

As to the F/M redesign of the AFB by their accountants currently being sold by another company - I won't go there at all.

Jon.

[4dblnkldude]

Cliff, nice thread, very informative. Same deal in the HVAC field with not touching things.

[Bruce Meyer]

Back in 69 my mother bought a new 69 GTO Convertible. The only problems she had with the car was the carb. It was in the shop multiple times for that. There are no "magic carbs" They can all give you problems.
With that being said, I don't know why anyone would bother with those Street Avenger carbs when the 4150 is tried and true. I have found the Holley 4150 very reliable except when you let them sit and dry out for very long periods (6 months plus).

[geeteeohguy]

I've had good results with Holleys over the past 40 years.... my 1915 Ford has an original brass updraft Holly G on it that works just fine. The Holley 4 barrels I've used in the past always worked fine for power, but always used a lot more fuel than the more scientifically calibrated Q-jet. My '67 GTO is running its original, born with Q-jet with 252,000 miles on it, and gets over 20 mpg on the open road at 75-80 mph with the retrofitted 2.56 rear gear. ANY time I see guys on TV or at rod events running an Edelbrock AFB copy in place of the stock, superior Q-jet, I think "COP-OUT". Great post, Cliff, but you're too reckless with your free time! LOL...........

[Ben M.]

Originally Posted by Cliff R

I wished I hadn't touched it, fearing that I had now "married" this job.

This is such a big problem for me that I'm to the point where I have a hard time just giving a friend or associate "advice" on what their potential problem is much less actually touching someone else's botched mess. All of the engine builders in the area I know of have insisted on these shiny aftermarket parts as part of their "package" and will void your warranty if you don't use them. Personally... I don't even bother with ANY new shiny part if the factory stock parts are in good shape.

I still get people giving me grief over using quadrajets, in over 15 cars in almost 20 years I've never used anything else except for one car that uses the Rochester 2bbl and never had a problem with any of them.

[Dragncar]

A Q Jet properly done has been said to be the closest thing to throttle body injection of any carb. They are the best at what they do.
The lingo of the wanna be mechanic should have been enough to make him run away like his hair was on fire. Thought those guys were just about gone.
Reminds me of a crew that showed up at the track with their pile Nova, ratty 350 with smog 1.94s they thought were "camel hump 2.02s", Tarantula intake, Holly 600 single feed with metering plates, highway single leg gears and wondered why they ran 15.90s.
One of them said " all we need now is a SUPER COIL". I left them to their devices.

[arcitech]

Flashback to my 1967 Buick Riviera (it was Dad's car at the time...1980ish). Got the car with just under 100k on it, still in great shape, but the thing would only get 10mpg in town and 10 on the highway! Dad and I replaced the spark plugs, distributor cap, rotor, points, and put a rebuild kit in the Q-jet. First long distance trip I took my senior year of high school it got 19-20mpg on the highway at 60mph! 4200lbs, Buick 430ci and TH400 with the Switch Pitch torque converter. I could pull a quarter mile run just under 17sec around 89mph, with 4 teenage idiots in the car (me as #1 idiot!). Drove that car all over and never had to mess with the Q-jet, she just purred and kept pulling! Still miss that car...

[Half-Inch Stud]

Great read CLIFF.

[NeighborsComplaint]

Holley Street, Truck and Ultra Street Avenger carbs are all vacuum secondary. Where did your friend find an Avenger double pumper?

[android 211]

The earliest Qjets put in Toronados had a reputation for setting the car on fire. However I had 'pure stock '66 442 4 speed with 3.55s that would pull 17-18 mpg on the Pennsylvania Turnpike cruising at 3000 rpm at 60 mph. I thought that was pretty good for a car that obviously had some kind of performance cam in it even if it was factory. All I ever did was tune it up.

[salem1912]

Originally Posted by steve25

Incredible!
He is lucky his new rings are not washed out!
Yeah , those Q-jets man ! Garbage, that must be why GM used millions of them and even Ford used them because they wanted buyers to come back day and night for warranty work!

And Dodge too!