Understanding Your Quadrajet - How Does the Quadrajet Work?

[@1967davethewave]

Probably the most advanced a carburetor will ever get since fuel injection killed the need to spend the money for a better carb. They are the best street carb I know of and will work excellent as a race carb in their power range. And of course who doesn't love that "Quadra Jet Drone" when the secondaries kick in!!!

[@robertwest3093]

My favorite carb hands down. I've even used them on 302 Fords 😁

[@chrisbraswell8864]

Works just as a Carter AFB. Wonder who they copied. you can change the Metering rods on a carter and completely change the carburetor jetting by removing two screws and covers and pulling the vacuum piston and metering rods out and they are easily changed to another size. That is so easy a 10year old can do it. Carters work great and was GM's and Chrysler Performance carb for years before the Q-jet. Nothing like the screams from a 389 Pontiac or a screaming 327. We always called the Q-jet the Quadro-bog. My GTO would smoke any tire from 0-90 mph in low gear. Power glides, made to break behind a 389.

[@billycarpenter4740]

I had Q-jets on several of my engines back in the mid-later 1970's. A bit harder to rebuild than Holley's but overall a better running carb for me. Hearing the back barrels open up under hard acceleration was always appreciated.

[@MikesCarburetor]

Its all about getting them adjusted properly.

[@ericburns2421]

I still use Rochester quadrajet carburetor

[@MikesCarburetor]

Once you get them dialed in they are hard to beat.

[@imtheonevanhalen1557]

My brother had a '66 Buick Skylark with a GS 350 engine mounted to a powerglide....if you've never sat in a car and heard the Quadrajet moan.....man, that damn thing sounded like a jet engine firing!! Swear to god, he'd put a set of recaps on the rear on a Saturday, pump the air-shocks all the way up.(a thing back in the '70's...) and it would be a cloud of white smoke chasing that damn thing going 60 mph......tires would be done Sunday evening.

[@1967davethewave]

That is a great engine to swap into a '66 Skylark. It must have been a real runner!!!!

[@imtheonevanhalen1557]

Scary as hell....Skylarks were super light!@@1967davethewave

[@MikesCarburetor]

I forgot about the air shock thing, but I couldn't afford them when I was a kid. With my Chevelle I put those Aluminum twist thingys between the spring coils to raise the rearl.

[@joe-hp4nk]

The fuel bowl gets sucked dry in a race application and a smooth air flow through the top of the carburetor doesn't cut it. Other than that it a good all around carburetor for your low output daily driver.

[@downback5822]

They do have the issue of fuel starvation with cheap standard rebuild kits.(.085 seat), but you can get them up to around (.145 seat), but then you have to be careful because it makes it harder for the float to control. With a good volume pump regulated to a little lower pressure no problems. Love them. Maybe I am making less power, but mid 10's in a 3500# car was ok I thought. Down side was having to collect dozens of them for rods and jets

[@1967davethewave]

Yes, the ultimate power potential is limited by the single inlet and the rather small single bowl. Even with a large needle and seat you simply can't flow enough fuel at the highest pressure you can use. If you could crank the fuel pressure up to 50psi you might be able to fill the bowl but at 9 or 10psi it will get sucked dry or at least too low to keep proper balance. I love them. They are far more advanced than a Holley for street driving but everything has a trade off.

[@joe-hp4nk]

Carburetors need volume not pressure, 5 - 6 psi is all you need. Racing engines with big Holleys use 1/2" fuel lines. You must be doing something right, but holleys are far more efficient today than the early days. @@1967davethewave

[@justinsane7128]

Good to see ya Mike.. I was never good with a quadra bog...

[@MikesCarburetor]

Information is always helpful.

[@RussellCompton-fh3gr]

great info,,,,,Love the look , do you nickel plate them for that finish ? do you sell throttle bushing/reemer kits to ? thanks

[@MikesCarburetor]

Sorry no throttle shaft kits. The company that did this carb bead blasts them to look good. Don't know what bead they use, They are no longer in business.

[@RussellCompton-fh3gr]

thanks for the reply@@MikesCarburetor

[@middletownman6278]

Hard to keep the bowl full of fuel and more delicate to handling than a Holley or Edelbrock. I have bought nice ones for $50 but it took a $1000 fuel system to make it work.

[@Spiritof_76]

What kind of ET are you running to run out of fuel?