Hello All,

Looking for carburetor recommendations for my 1978 Silver Anniversary Edition with original L82 engine. Quadrajet carburetor rebuilt four years ago but thinking about Holley now. Any recommendations would be appreciated.

Thanks,

Tom

 

Send your Q-jet to “Lars”.

Steve O.

 

Do you have any contact information?

 

I think email isV8FastCars@msn.com

can you post pics of carb? How was it rebuilt previously?

my 79 Lars rebuild is fantastic still..

 

If you go to a Holley then you have to change the intake too. Adapters are trash. I too would opt to send it to Lars, but send him pics first. It is possible that your carb was rebuilt so poorly that evens Lars can't repair it.

 

The Holley is a good idea if you'd like to lose 15 hp over your stock 800 cfm High Performance Q-Jet. If the car is too fast, switch to the Holley. A 600 "Street Avenger" would be perfect to cut the performance down to the "Valet Parking" performance level, or if your son wants to take the car to Prom...

Lars

 

Never, ever, wishing to counter act anything Lars has to say.
But here I am. I'll explain my experience.
A long time ago. I had a quadrapuke carburetor. It came on my car. As I would sit idling at the light with a little Ford pinto next to me. My car idled fine. The light turned green, the 4 cylinder death trap was long gone as my beautiful Corvette coughed and chugged it's way slowly to 20 miles an hour. And then, with the little ford long gone. And I mean LONG GONE, my Quadrapuke finally kicked in, and away I'd go!
So utterly disappointing.
I tried rebuilding it. No joy.
I had others who claimed that they knew all about Quadrajet carburetors rebuild it.
4 times it was rebuilt. 4 times it sucked!
I did not know of Lars way back then. Only local guys who claimed they knew.
I had enough! I thought, I'll purchase a new quadrapuke! Back then, I was buying parts from Ecklers, (this is long before they became what they are today). Ecklers wanted as much for a correct Quadrajet as I could purchase a Edlebrock intake manifold, Holley 670 carburator and all the gaskets and bolts for.
On went the 670 Holley. A fair few things needed to be sorted from vacuum lines to cable brackets.
Result.
My car left the lights like a bullet out of a gun!
Full stop!
WOW! what a improvement!
a little less top end I did see.
But the improvement in bottom end and mid range was so profound it was more than worth it!
Yes, I did have to dial in the Holley. But myself and most mechanics COULD dial in the Holley.
(There relatively simple that way).
So no, I didn't just bolt something on and go. Everything from the vacuum line to the power brakes to the fuel line to the cable bracket had to be modified. And my hood wouldn't close!
difference in performance was profound!
But I didn't know Lars. Didn't know what the internet was back then.
I just put on a high rise hood. And enjoyed my car!
For the first time since I had owned it I might add!
So,
Bottom line.
More than one way to skin a cat!
Think all this over. I got there in the end with a manifold, a Holley, lots of rearranging with vacuum and fuel lines. Brackets and such. And yes I went with a different hood and the paint to match rather than a restrictive drop base air filter.
Or, and I didn't have this option many years ago.
TALK TO LARS!

 

If Lars thinks it is a rebuildable carb then IMHO send it to him. The cost of having him rebuild it will be much less than a Holley and all the fixings. And yes, I had my 78 L82 qjet rebuilt by Lars and could not be happier. Out of the box, back on the engine, and drove the same day, nothing to change.

 

Remember that our friend Lars actually installs your refurbished Quadrajet on a test engine! After running the engine, he will go back and make any required adjustments. The mechanic that installed my OEM intake manifold and OEM carburetor from Lars, didn’t have to make adjustments, because everything was set up perfectly.

 

The L-82 Q-Jet is in the top 5 of best Q-Jets ever made. Have Lars refurb it.....

If you decide to run a Holley square bore carb then you must replace the intake manifold......the very best Holley on the market for mild 350ci engines is the 0-90670 Holley Truck Avenger......

Jebby

 

Lots of Holleys used for lots of years, and the Quadrajet, while when functioning properly is more than adequate for most, there seems to be only a few people who can rebuild them, and most of them have been butchered up by "professionals". My Holley Street HP Aluminum, recommended by Jebbysan, is one of the few things that worked very well on my 406 SBC, and I will be using it again on the new engine.

Whatever "HP loss" a Holley supposedly creates is irrelevant on a street car.

 

Another vote for send it to Lars.

 

If Lars is taking in work I would send the original to Lars and have it redone.

I have had good results with the Quadrajets , Holley and Edlebrocks but I have never had to repair a butched up Quadra jet either like Lars does . Tons of Mopars out there with AFB's and AVS's that run fine and I have converted four or five late 70's 351/400M Ford pickups with factory two barrels to Performer and 1406 and they run great

On a side note I am going to do some back to back testing/shoot out between my 1980 L82 Q jet to a Edelbrock 1406 . I'm doing the test to evaluate the TV system of my 1980 L82 700R4 conversion. The Edelbrock has the TV corrector for the 700 mounted, I do have the TV dialed in pretty good with the T350 throttle lever on the Q Jet with 700R4 but want to see if cruise-ability will improve with the 700 . If the cruise is way better I will modify my Q Jet throttle lever for better result .... I already have a Edelbrock 2101 intake so I will verify and adjust fuel/air ratio between the two carburetors, check gas mileage and of course compare 1/4 mile times between the two carburetors , should be fun

 

If the Corvette Forum were the US Supreme Court, it would be a unanimous ruling to send your QJet it to Lars.

Case Dismissed.

 

I don't send mine to Lars LOL He is grateful for that too......

Jebby

 

It is important to have a good understanding of carburetors and intended applications as well as compatibility to know how to really spec out a carb........
But here is a list of my most recommended units:

Stockish up to 375hp wanting a stockish look........if you have it or can get one, the Q-Jet simply cannot be beat. They work so well that I spent some time locating over a half dozen cores to refurb......I went from a 600cfm single feed Holley on my 5.0l Z/28....no difference in 1/4mile time but fuel economy went up about 3 MPG.......

Mild build 350-383ci up to 400hp (I have run it on my own 500hp 406 to prove a point but was down a little upstairs....) 0-90670 Truck Avenger 670cfm, billet annular primary boosters.....dead on 350hp calibration "window".....simply the best carb I have ever used in this performance range. I have one here as a test carb, I put it on a 340 Demon in 2010 and when I redid the engine he gave it to me for a 750 Mighty Demon which was a better fit.......after 10 years and 6000 miles it has and does perform flawlessly.....it was never cracked open until I jetted it for my 406 in 2021........
Lars sent me an E-Mail over a year ago of a 67' L-79 327 Vette that had a crapped out original 585cfm and put a 670 Truck Avenger on it. All he had to do was remove the goofy vent and put a yellow spring in the secondary......he told me it made a new car out of it and also said he has been using these as well since 2007 when they came out......neither of us knew the other were using these exclusively........it is amazing how close the TA 670 resembles the original 585 too.....even has a secondary metering block.
My little brother needed a carb for his 331ci 1955 DeVille Coupe and I told him to adapt a 470cfm Truck Avenger to the stock intake.......I had to fatten it about 4 jet sizes but it was perfect after that......
Holley found the sweet spot median strip on the airbleeds and metering block passage sizes.......it has an awesome window of tunability......something the garbage truck Street Avenger will never have.....which coincidentally Lars told me he hates too without ever knowing I despised them.......

Hot street 425hp to 500hp the Holley 750 Street HP is also flawless........I told my customer and friend (member Street Rat) to buy this in 2021 for his hot 355 and when I built his 385ci he put it on there and with mild jetting change it runs flawlessly......crisp and responsive everywhere......

Over 500hp I go straight to the Classic 750HP or 850HP.......I run the classic 750HP........the 406 may make 10-20 more with an 850 but I like the response and tractability of the smaller carb......

600hp+ 950 Classic HP done by Patrick at Pro Systems or AEM........both have a good handle on the characteristics of a 600hp fuel curve and demands......and also of the idle circuit......

The Classic 650 and 750 Double Pumper still work amazingly well......

You pay for these carbs and there is a reason for it.......

Jebby

 

It would be a split decision, and there would be wisdom to be found in the dissenting opinion(s).

Absolutely, if you want a Q-Jet on your carb, and Lars will rebuild it for you, that's likely the best option.

But if the current Q-Jet is not rebuildable again, then what? The OP should post some photos first.

There are specific Holley carbs that folks like. And there are EFI solutions, too. What does the OP want is the important thing.

 

Holley 4150 D.P.
You ain't ah chitin they run well.

The extra pump on the secondaries removes the infamous bog that Quads were noted for.

I like the adjustable float height setting while the engine is running.
I like the adjustable secondary throttle opening.
I like the fuel level sight glass or plugs.
I like the ability to easily swap squirter size and tweak the pump shot duration.

What's not to like?
An occasional fuel bowl / metering block gasket leak.

 

Double Popcorn LOL

Jebby

 

My friend has a 78 L82 4spd and many years ago exchanged his Qjet for a Holley. He bought a Holley, 650 CFM spreadbore, electric choke- 4175 (https://www.holley.com/products/fuel...t/parts/0-9895). He uses the original alum intake manifold and original dual snorkle air cleaner. It has done him well even after an engine rebuild. Would there be a reason other than cfm to not buy this for just a street driven Corvette, if the OP absolutely wants a Holley? thanks