I just got my first Vette, and I would like to replace to stock carb and intake manifold. I was planing on going with edlebrock on both of them. PERFORMER SERIES 600 CFM for the carb and Performer manifold for the intake. I was just wondering your guys input and see what you thought. Have any one used this kinda combo/is it worth it. and info would be helpful. There are other things I plan on doing but this has got me stuck with choices. Thanks

 

The carb you have is better than the carb you want to put on. You won't find any significant performance gain from switching the iron intake to the basic performer, but I'd be willing to throw a performer on solely to avoid having to lift the iron intake back on - if I were changing the intake gaskets for some reason.

 

Long tube headers first

 

any particular kind?

 

I'll say it more emphatically:

The Q-Jet carb you have now is MUCH better than any [antiquated] Carter AFB wanna-be from Edelbrock. Now, if you want to change the intake manifold to a better, Edelbrock spread-bore unit...go for it.

IMO, you can't do any better than a Q-jet on an engine that needs 750 cfm (or less) airflow. Just clean it well, rebuild it (or have it rebuilt), and use it for another 40 years.

P.S. The Q-Jet is capable of flowing 750cfm. But, it only flows as much as the engine, to which it is installed, requires.

 

Tuned ceramic coated headers... There are several good ones, mine are dynomax.... I think hooker or headman are better though.

Well, yes and no...... Yes for stock or near stock...... I run 460 hp to the rear wheels, and run a mighty demon 750 annular double pumper, I do not believe the quadrajet would keep up with my bg for my motor.


To the op.... You going to build a race car, or a cruser? Cruser, stick with the Q, if your building a race car in the long run, start with a list of the final build, then buy it piece by peace..... I did a lot of that, then you won't have to buy twice?!?!?! O, and if your going to build a race car, holly or Deamon. IMHO...... Others my disagree or agree.

 

I did the edlbrock intake(kept my rochester q-jet) and then did headers. very noticeable difference with hp from doing headers, not so much with intake and carb clean. since your ready to drop $500-700 for intake manifold and carb, use that toward exhaust system. advance auto will send to your house everything you need, from headers all the way back to mufflers. the pipe kit they sell is hooker so i would get hooker headers. i didnt and it caused me a lot of problems because the headers I got sit lower and i had to do some serious "tweaking" to between the header collector and getting the pipe through the tranny crossmember holes.

 

That's a good way to lose 20 horsepower: drop the carb size from 750 to 600, and use a less efficient carb (that was deemed obsolete and discontinued by GM in 1966). Please send me the Q-Jet when you remove it: I'll pay all shipping charges. E-Mail me for my address. Disregard anyone else with the same offer:

Lars
V8FastCars@msn.com

 

Headers and a solid tune first. A dyno tune will typically find a fair bit of power and throttle response.

The Q-jet debate rages, but it's an outstanding street carb. The only - only - downside to it is that tuning expertise and parts can be difficult to find. I would expect that it's tired, however - so invest in a good overhaul; there are only a few folks that can do it right and a search here will reveal them all Do not - do not - do an exchange or have it overhauled by a "mainstream" shop.

 

Learn all you can about the Q-jet. It will pay serious dividends.

http://www.amazon.com/Rebuild-Modify...=cliff+ruggles

You can get someone else to fix it for you, but then who is going to fine tune it for you?

 

This is the best deal you could come across. Lars is the "best of the best"

 

Roco - re-read your quoted post. Although I'd much rather an unwanted Q-Jet go to Lars than to the garbage can.

 

I don't want to get into an "opinioned" debate...but I defy anyone to provide any substantive proof that a Q-Jet cannot perform just as well (or better) than any other carb for a racing application. Most of the Holleys and re-pops of the old AFB carbs just dump fuel into the secondary system at WOT. Big deal. Any carb can do that. At least the Q-Jet allows the owner to "dial-in" how fast that fuel should get to the engine.

All carbs can be set to run about equally well at WOT; that is a simple matter of fuel flow and airflow. Holleys have been perceived as being the better 'racing' carb for decades. Even GM used that "perception" for marketing purposes by putting Holleys on top of their "High-Performance" engines. But, they also put Q-Jets on the 390 hp 454's, while still installing a Holley on the LT-1 which puts out much less HP/torque. Marketing.

I'm interested in seeing any data/articles that have rational info about the benefits of ANY carb brand over use of a good Q-Jet, if there is any benefit to be had. Anyone can install any carb they want on their car. I just find it irritating when folks advise others to discarb a dang good carb (Q-Jet) for another brand, solely because of some personal bias. My philosophy has always been to use what I have available before discarding something....as long as it is functionally viable.

I highly recommend that the OP send that carb to Lars for some "TLC", then reinstall it on his engine.

 

you just got into the OPINION debate....

im not saying the Q is bad.... just not the best for racing.... when was the last time you saw ANY pro race car with a Q?

 

Agreed, 100%.

Once your CFM requirements go beyond a certain level, you're forced to go with a different design because the largest carbs were ~850 CFM.

That said, there are street/strip QJets pulling low 11 second quarter miles, which is pretty damn fast.

I'm sticking with my QJet. After reading Cliff's book over and over, I can tell you 2 things.

1. Quads are more complex than I originally thought they were.
2. The complexity adds significantly more tunability. You have accel pump, secondary POE (which acts like an accel pump when the secondaries engage),secondary hanger size, secondary tip size and length, accel pump squirter size, idle fuel tube outlet size, down channel restrictions, bleeds, idle bypass air...

The primary system on quads is sweet. The crappy part is the amount of time it takes to dial them in, but no power valves to blow and a really cool primary metering circuit that gives you cruise, WOT, and idle adjustability.

 

ok... ill put this out.... going to do another dyno pull in the next month or so.... send me a Q and ill run it back to back to my mighty demon....

lets see what the results yield

 

Paul - does your intake accept spread bore quads?

 

 

Would have to use an adapter plate

an amazing offer form the best

 

The point not taken here is the Qjet will power a 180 HP L48 up to a 500+hp big block with minor tuning changes and give excellent street performance, fuel mileage and likely better throttle response. Probably won't give anything up on the ET slip either. Holleys are easier to fine tune at the track and parts availability is better. If nothing is wrong with a qjet don't ever replace it.