Hey guys,

So eight months ago I bought a remanufactured Qjet from Ecklers and now it's doing what all reman Qjets do. It's running way too rich and I would really like to switch to either a proper Qjet or a Holley instead of rebuilding it. I don't think I can even find a rebuild kit since I have no idea what kit even fits it

I'm currently in between two choices (I'd rather go with the 2nd choice):

1. Buying a brand new Holley spread bore 650

2. Spending less on a very well done Qjet

The Holley carb is ~$650 which is a bit excessive considering that I have to tune it and redo the brake booster connection and probably the fuel line

I don't have the experience or time to research and buy a correct Qjet core and build it all the way up from the ground so that's also why a brand new Holley seems like a good choice. Again, all I'm looking for is something reliable.

I rebuilt the previous carb that was in my corvette which was a horrible reman carb from a checker bus so I know the basics when it comes to Qjets so tuning it would be easier.

I don't know where to find a good quality remanufactured or rebuild Qjet the best-looking one I've found is a 7042202 carb for a 1972 corvette, my car is a 71 but it has a 5/8" fuel line on it so the later carb makes it so I don't have to replace it
https://quadrajetpower.com/chevrolet...rajet-7042202/
I don't know if these guys are any good and if anyone knows where I can get a really good quality Qjet please let me know
I'm willing to pay the difference if it means my carb will last

 

Search for username Lars and get his carb papers.

 

I've already read a few of them but my question is in terms of reliability is it better to buy a new 650 spread bore or a really nice Qjet

 

I know you have a spreadbore Intake, but is it stock or an Eddy 2101? The Eddy will also accept a "squarebore' mount by simply moving the carb studs. This would give you more options for carbs or a better Holley 4150 series.

 

I have a stock intake manifold

 

Unless you find a left over new in box edelbrock quadrajet anything you find will be over 40 yrs old and may be warped stripped out screw holes leaking plugs on the early ones. I'd do the holley in a minute. There probably won't be much tuning.

 

Well, that's the end of that.

But, do not use any adaptor to put a Holley on a GM spreadbore. Ever.

 

Wait so will the Holley spread bore fit on the stock GM intake manifold?

 

yes, 80555c Holley

 

Holley has made the 4175 forever find a used one really simple basic carb. Close to $600.00 for a new one is highway robbery.

 

Has to be a better price out there!! Paid just under 500 for a custom built AED 850 HO (Chris Straub got me a killer deal)
OP maybe your plug on your quadradet is leaking, epoxy that sucker shut and use it?

Both are reliable carbs imo hard to go wrong eithe rway. I used to have a holley spreadbore on my Camino, DD it for years never once touched it. Same for the dailies that used Qjets...todays Holleys are pretty good they dont need fooling with all the time like the ones of the 70s/80s

 

Did a quick search and found this Holley 4175 for $150 free shipping used...buy a rebuild kit for $50 from holley or less elsewhere, rebuild it yourself and you are in business for about $200, assuming the core holley is decent.......

https://www.ebay.com/i/312993472038?...gaAtEsEALw_wcB

 

Over the summer....and not even looking......I found two excellent Q-Jets in 8 out of 10 condition......bought both for $75 each. One was on FB and one was right here in the parts section.
The first is a 77' 350 L-48 carb and the second was a real score, a 1906 Edelbrock in almost perfect shape. If you look.....they are out there.....and would be what I would do. Q-Jets still have a stigma to the uninformed....therefore the only people that are buying them are knowledgeable hobbyists who know what they are looking at......a quick search found this: https://www.ebay.com/itm/1978-Chevro...QAAOSwa5ZfQVmQ all it needs is the accel pump lever.....which you have
The first Q-jet I bought sat on the shelf 60 days before it found a home on a 72' 350/200........I am keeping the Edelbrock for myself unless someone had to have it.....
The Holley works very well......a lot of people use them with great success, but the cost of admission is high, and I do not believe they are as responsive off idle.
Good Luck on your search....

Jebby

 

Holly used to make that in a double pumper model, that takes care of the responsiveness issue. So. You have some choices, and that's a good thing

 

Why don't you contact Lars and see if your current Q-Jet is salvageable? He is one of a few Q-Jet gurus in the country.

It all depends on how many internal parts like rods & jets & hangers got mis-matched during the rebuild.
It might be a simple fix... or not.

A well running Q-Jet is an excellent carb, and very dependable. Just not the easiest thing to tune yourself.

 

More than likely. That was Holleys intensions, to have a "bolt-on" carb for all those billzillion GM spreadbore Intakes.

On the GM spreadbore Intake plenum as you know, are two small primary holes that match the QJet throttle blades.
At the rear of the plenum is is the larger holes "spread" out.

But the real story here is the bolt pattern or the carb stud locations. That is what diffiates QJ spreadbore from Holley Squarebore, the bolt pattern.

Google: pictures of Edelbrocks 2101. This will show the plenum and optional bolt patterns.

 

OK, so I'll be able to get more use out of the reman carb I currently have on my car. I was able to tear it down and I found out that the filter was completely full of orange powder and was long overdue for a replacement.
After a thorough cleaning and lowering the float level a tiny bit, I'm hoping the carb is going to stop gushing fuel out the top like a water fountain. I'm not sure a rebuild kit will do much because the components inside have only seen 8 months of use and look pretty new

I read through Lars' tuning guide for Qjets and he mentions that starting off with the stock rods and jets for your current serial number carb is a good starting point. I'm hesitant about doing this because the stock tune for my 1987 GMC truck carb is very lean compared to the 1971 corvette carb

What do you guys think about tuning the 78 truck carb with the same or very similar-sized rods and jets as the 1971 carb and using that as a starting point?

Of course, I'll have to buy 1975 and after primary rods due to the size difference.

I saw somewhere that you want to tune carbs to be slightly richer than the stock tune because modern fuel burns quicker or something like that. Can anyone confirm if this is true or just bs?

That makes the most sense to me and currently, I have no idea what's in the carb because the primary rods have no size markings and the markings on the jets are illegible.

The secondary rods are good and the power piston spring should be but ill get a few if I buy new rods and jets.