I have a 74 vette with a quadra carb. I was told that I should replace it? What's the advantage of replacing it and what carb should I replace it with. I'm looking at making my C3 into a nice driver, so I'm up for suggestions! I want to spend about $2500 on the engine performance wise? I'm not too mechanical but I do my oil changes and tune ups. The bigger stuff I want to leave for the shops. Also, taking my vette to a vette specialist or regular mechanic? A difference?

 

You have recieved some bad advise. The quadrajet is a great carb, especially for a street driven car. Any after market carb you can buy will be a down-grade.

God bless, Sensei

 

Do we really have to go through this *again* about Q-Jets?

http://forums.corvetteforum.com/1574054168-post9.html

http://forums.corvetteforum.com/1578781815-post24.html

As for the shops, much of the Corvette is just regular Chevy stuff...but much of it is also not. Best to work with a solid Corvette shop than a good general mechanic.

 

I know this thread is a setup, but whatever.
Anybody who thinks a carb change from a quadrajunk to a 750 Holley is a down grade either owns stock in quadrajunk or is an idiot.
A quadrajunk is a lean running, small primary, secondary bog king that would take its weight in dollar bills to out perform a $300 Holley.
If a person were to swap out the original carb for a performance Holley and the car ran worse deserves the results.
Bolt on a Holley, get a good throttle bracket to give you all your pedal and you will have 1000% increase in performance, if you don't then refer to above statement and start over with someone who knows how to setup your car to run right.
Or on the flip side of the coin, just spray down the original quadrajunk with carb cleaner and shut the hood and get the same results as shoving huge loads of money in it for the same results and park in the backyard and drive your Yugo to bingo Wednesday night and hope you win the cover all so you can buy a carton of cigarettes at the outlet mall Thursday morning on your way to the country buffet breakfast club.

 

Wow!! 1000% you should be able to break the land speed record
Sounds like you have a L48? I would make sure the quad. is working properly. Reset the timing curve (lots on the forum about this) and put money into an exhaust system you really like. Sounds like you just got the car. Your going to NEED the extra money for other fixes! Ask anyone on here

 

What a load of BS. Personal preference aside, the quadrajet if tuned well, performs as well if not better on the street than anything else out there. Why do you think there are so many thousands that were put on cars in the first place, and not just by GM? The key is tuning one correctly, and not everyone has learned how to do that. Holleys can be tuned pretty easily but have their own issues too. The quadrajet offers small secondaries to promote better fuel economy at cruise with large secondarys for performance when you need it. If the carb or the engine aren't tuned well or there's some other issue you'll get the bog, but that's a symptom that somethings wrong, not a design flaw.

Basically, the Q-jet is a good choice if you want to stay with it. They really aren't that difficult to re-build, but if you haven't done it before, do your homework first. If you're not inclined to do it yourself, there are several rebuilders that have very good reputations.

 

Well Tim, in spite of the fact that you just called me an idiot:

I have worked on about every brand of carb out there. I am not a Quadrajet only guy. If you are building a motor for the dyno or a car primarily intended for strip use, you want the simple tunability of a Holley (although I would avoid newer untits due to quality control issues).

For a street car, where fuel economy is a consideration, you want a Quadrajet. You like to say they run lean. Well so do Holleys that are tuned lean. In the 60's, there were many brands of carbs that came on production vehicles. In the 70's when emmision regulations were getting tighter and tighter, the precise tunability of the Quadrajet made it the only carb that could walk that fine line and still be usable.

Carbs mix fuel and air. Period. Thay are all tunable. Most have a cruising mode and a WOT mode (2 set fuel ratios). Quadrajets can meter fuel at varying ratios through 3 separate circuits, two of which adjust the ratio according to engine demand at the time. No other carb does that.

A qudarajet can be tuned as rich as you like, just like any other carb. They are not simple like Holleys, so you have to know what you are doing to tune them, It takes a bit longer, but done correctly, they will mix at the optimum ratio for WOT performance (i.e. make the car go as fast as any other carb), and at the same time give optimum fuel economy throughout the driving range. Other carbs just don't have that adjustability.


My '81 is a tire shredder that gets 23 mpg on the highway (and I drive it more than 4 hours almost every day). Perhaps if you quit insulting people who know more about these things than you do, you might actually learn some things so that a 4 hour, no break down drive is no longer a boast worthy event for you also!

God bless, Sensei