They also used those on the Pontiac 250 CID OHC 6 cyl. Sprint engines in the A and F body cars. I've always kept the original Quadrajets on all my cars from the 301 to my current 455 Trans Am and always had a fast car with great throttle response and driveability. If you set them up right, they're trouble-free for many miles!
You're 100% correct, two Q-jet CFM ratings, 750 and 800. Iv'e been a Pontiac guy all my life owning GTO's and Trans Ams. I some how got into rebuilding and calibrating Q-Jets for Pontiac enthusiasts and my own Pontiacs and I was wondering if you guys ever saw a factory single boost primary Q-jet? The're really a odd duck. I've had three of them in my life time, they were installed on some 1971 GTO's and they flowed 800 CFM. They really ran strong! I ran one on some of my Ram Air lll's and a Ram air lV.
Great tips about the two sizes. I always thought they were a 650 but, good to know they are a 750 and 800 only. To me many people think they are junk so, they are cheaper to pick up at swap meets. I always love to pick them up since people always want Holley's instead.
Same. In Oz it was really common for people to rip the Quad straight off their Holden and replace it with a 600 Holley. I never understood how that was an upgrade..
They were rated at 750&800 cfm. Nothing they were ever used on could ever pull enough air to max them out. They were always sized perfectly because they only flowed what the engine could pull.
Excellent video. I got a 383 stroker coming to replace my stock 350 in a 78 k-20. Its supposed to have 410 horse. 750 cfm means I can use my 350 intake, and quadrajet.
Great video. That's what I've always loved about the Qjet...it's infinitely adjustable. And that's why they came on practically every kind of engine application found in an automobile. Engines that had to start and run everyday in all traffic and all weather conditions and STILL deliver high performance when it was called for. If Edison invented a carburetor it most likely would have been a Qjet. Thanks again and Semper Fi!
They even use these carburetors on a lot of boats! I have a OMC 4.3L V6 with a 750 CFM Quadra jet! Factory horsepower rating is around 220 I believe! It runs almost as good as a fuel injected engine!
Hi James, this was one of the best videos I have seen on the Rochester Q-Jet carb. I have a 1981 Trans Am which I purchased as a young man back in 1989. I since removed the 301 turbo and replaced it with a 1968 Pontiac 400 with HO heads period correct and it has an Edelbrock square bore intake. I bought the engine complete and had a speed shop install it back in the mid 90's The carb on it is a Holley 750 double pumper, yes I know what your saying, its way to big and yes I figured that out recently. (note this car was in storage from 1996 until 2018) I was hoping I could speak with you briefly on what direction to go in regards to the intake and carb combination as I'm seriously think of going back to the stock intake with a Q-jet carb. Please advise
Feel free to reach out , the shop phone number is 631-560-1545, if you don’t get an immediate answer, please leave a message and I’ll get right back to you. Thanks for the compliment
I have a 1980 Pontiac Grand Prix SJ 301 Engine W-72 has Spark Detonation sensor. 170 horsepower, Quadrajet carburetor. But from the Factory, and I bought it new. The top Secondary Air Valves. Are set to open only to 3/4 . The factory has a small. tab Added on outside end of the Secondary Air Valves shaft. On the right side. Too keep Air Flow down. I know for sure, that is why they did it . Because, I cut down that Tab. AND THE ENGINE COULD NOT TAKE that BIG FLOW OF AIR. ENGINE RAN real bad .When I Floored the Throttle . SO I HAD TO ADD METAL ON . TO STOP SECONDARY AIR Flaps FROM OPENING TOO MUCH. I checked up on that. YES , that is how on cars that had a lot of Emission Things. And the Exhaust was small. General Motors - Pontiac , cut back the Air Flow. That Carburetor would, put out .And would flow in and out of the Engine . And the Engine runs great now again . I bet it now flows maybe 680 CFM to 700 CFM of Air.
I found one from an engine that sat in a shed on a 400 Pontiac didn't do a thing to it stuck it on my 305 and it runs fine starts good throttle response good it is an 800 I believe wanna trade for the one I need for my 305 it was a 78 transam motor sat in the shed since 99 lol
So I’m sitting here watching the video and I’m thinking, “I need to find a local place that has this kind of knowledge” and then I notice the phone number, is that a 631 area code? Suffolk? I’ll have to look this up
Nevermind about the Poncho question.lol Was it a LEGIT GM/Pontiac advertisement?.....or was it some mom n pop dealer or just someone selling the car going over the different stats?
Sorry just saw this guys, my opinion 500 is a stretch, Q jets are somewhat limited in the amount of fuel that flows through one needle and seat assembly. I’m sure there are guys out there that made in excess of 500hp with there quadrajet but I’m pretty sure they would make more with a Holley. Just my opinion
Yes. Shave a 1/4 " off the bottom of the plastic/phenolic float bowl insert and install the smaller '75 and later float to free up volume better used for more fuel. Install a .135 needle and seat for starters and experiment from there. Install a HIGH VOLUME mechanical fuel pump like a RobbMc and utilize the fuel/vapor return line. You may also need to enlarge the idle tubes and idle down channel restrictions a few thousandths(like one or two at a time) for a better idle quality, control of the mixture screws, and higher vacuum. For safety use a METAL fuel line from the fuel pump to the carb. NiCopp works great and is easy to fabricate with. The pleated factory style fuel filters located inside the carb inlet are fine unless you have an 11 second car.
Nothing sounds like a quadrat jet that sound is unmistakable
They also used those on the Pontiac 250 CID OHC 6 cyl. Sprint engines in the A and F body cars. I've always kept the original Quadrajets on all my cars from the 301 to my current 455 Trans Am and always had a fast car with great throttle response and driveability. If you set them up right, they're trouble-free for many miles!
We had an old Chevy van at work, 220,000+ miles. The quadrajet carb on it looked liked a big lump of grease; Van always started and ran perfectly.
You're 100% correct, two Q-jet CFM ratings, 750 and 800. Iv'e been a Pontiac guy all my life owning GTO's and Trans Ams. I some how got into rebuilding and calibrating Q-Jets for Pontiac enthusiasts and my own Pontiacs and I was wondering if you guys ever saw a factory single boost primary Q-jet? The're really a odd duck. I've had three of them in my life time, they were installed on some 1971 GTO's and they flowed 800 CFM. They really ran strong! I ran one on some of my Ram Air lll's and a Ram air lV.
Great tips about the two sizes. I always thought they were a 650 but, good to know they are a 750 and 800 only. To me many people think they are junk so, they are cheaper to pick up at swap meets. I always love to pick them up since people always want Holley's instead.
Same. In Oz it was really common for people to rip the Quad straight off their Holden and replace it with a 600 Holley. I never understood how that was an upgrade..
They were rated at 750&800 cfm. Nothing they were ever used on could ever pull enough air to max them out. They were always sized perfectly because they only flowed what the engine could pull.
They bellow
flat of cfm …
Laid one open for 4 mins to Wisconsin. Man that TA 400 2:73 geared . Never gave up a inch .
Excellent video. I got a 383 stroker coming to replace my stock 350 in a 78 k-20. Its supposed to have 410 horse. 750 cfm means I can use my 350 intake, and quadrajet.
Great video. That's what I've always loved about the Qjet...it's infinitely adjustable. And that's why they came on practically every kind of engine application found in an automobile. Engines that had to start and run everyday in all traffic and all weather conditions and STILL deliver high performance when it was called for. If Edison invented a carburetor it most likely would have been a Qjet. Thanks again and Semper Fi!
They even use these carburetors on a lot of boats! I have a OMC 4.3L V6 with a 750 CFM Quadra jet! Factory horsepower rating is around 220 I believe! It runs almost as good as a fuel injected engine!
Thats great information to know. I'm gonna have to rebuild my carbs on my 430 and 455 Buick engines. Great 👍 video
Thank You for the help
Hi James, this was one of the best videos I have seen on the Rochester Q-Jet carb. I have a 1981 Trans Am which I purchased as a young man back in 1989. I since removed the 301 turbo and replaced it with a 1968 Pontiac 400 with HO heads period correct and it has an Edelbrock square bore intake. I bought the engine complete and had a speed shop install it back in the mid 90's
The carb on it is a Holley 750 double pumper, yes I know what your saying, its way to big and yes I figured that out recently. (note this car was in storage from 1996 until 2018) I was hoping I could speak with you briefly on what direction to go in regards to the intake and carb combination as I'm seriously think of going back to the stock intake with a Q-jet carb. Please advise
Feel free to reach out , the shop phone number is 631-560-1545, if you don’t get an immediate answer, please leave a message and I’ll get right back to you. Thanks for the compliment
I have a 1980 Pontiac Grand Prix SJ 301 Engine W-72 has Spark Detonation sensor. 170 horsepower, Quadrajet carburetor. But from the Factory, and I bought it new. The top Secondary Air Valves. Are set to open only to 3/4 . The factory has a small. tab Added on outside end of the Secondary Air Valves shaft. On the right side. Too keep Air Flow down. I know for sure, that is why they did it . Because, I cut down that Tab. AND THE ENGINE COULD NOT TAKE that BIG FLOW OF AIR. ENGINE RAN real bad .When I Floored the Throttle . SO I HAD TO ADD METAL ON . TO STOP SECONDARY AIR Flaps FROM OPENING TOO MUCH. I checked up on that. YES , that is how on cars that had a lot of Emission Things. And the Exhaust was small. General Motors - Pontiac , cut back the Air Flow. That Carburetor would, put out .And would flow in and out of the Engine . And the Engine runs great now again . I bet it now flows maybe 680 CFM to 700 CFM of Air.
Do you have any videos on a 1965 -442 one year only carb? Thanks
I ended up having 2 800cfm ones. Been looking for a 750 for my 355sbc in k10. Guess a 800 will work..?
On a stock 400 1976 pontiac trans am would the carb from a 69 gto work well???
couldnt hear at time what you were saying.
I found one from an engine that sat in a shed on a 400 Pontiac didn't do a thing to it stuck it on my 305 and it runs fine starts good throttle response good it is an 800 I believe wanna trade for the one I need for my 305 it was a 78 transam motor sat in the shed since 99 lol
i just took a 750 and filed down the ridges and polished the barrels
So I’m sitting here watching the video and I’m thinking, “I need to find a local place that has this kind of knowledge” and then I notice the phone number, is that a 631 area code? Suffolk? I’ll have to look this up
So then why did a 76 poncho 400 have a Qjet 850 as advertised?
What is a Poncho?
Nevermind about the Poncho question.lol
Was it a LEGIT GM/Pontiac advertisement?.....or was it some mom n pop dealer or just someone selling the car going over the different stats?
Will a Rochester Quadrajet work well on an Olds 425, pumping 550-600 hp?
Sorry just saw this guys, my opinion 500 is a stretch, Q jets are somewhat limited in the amount of fuel that flows through one needle and seat assembly. I’m sure there are guys out there that made in excess of 500hp with there quadrajet but I’m pretty sure they would make more with a Holley. Just my opinion
Yes. Shave a 1/4 " off the bottom of the plastic/phenolic float bowl insert and install the smaller '75 and later float to free up volume better used for more fuel. Install a .135 needle and seat for starters and experiment from there. Install a HIGH VOLUME mechanical fuel pump like a RobbMc and utilize the fuel/vapor return line. You may also need to enlarge the idle tubes and idle down channel restrictions a few thousandths(like one or two at a time) for a better idle quality, control of the mixture screws, and higher vacuum. For safety use a METAL fuel line from the fuel pump to the carb. NiCopp works great and is easy to fabricate with. The pleated factory style fuel filters located inside the carb inlet are fine unless you have an 11 second car.
if you run class part number has to be correct
Nice thing is you can always recalibrate
I have an 800 off a 78 trans am ill trade for a good rebuilt one setup for a stock 305 this 800 is running it but i know it could be much better
mumble ... mumble ... mumble....
I've got a 1000 CFM Quadra-FLUSHER on my 455 shit box tuna boat...wtf u talken bout willis?
Dreamer
Mmmmmmm tooona