Quadrajet rebuilder
Racer
Joined: Aug 2007
Posts: 267
Likes: 0
From: Springdale Arkansas
I would not buy a carburetor from anyone that will not or does not have access to dyno them. The most minor adjustments on these carbs are worth 10-30 HP. (seconday side)
I do not build carbs anymore, When building them I only fooled with Q-Jets. They are the best carb ever designed and will deliver fuel injected mileage when properly built. They will also spank a Holley on the dyno when properly prepared.
www.jimboscarbs.com
FWIW, Jim
I do not build carbs anymore, When building them I only fooled with Q-Jets. They are the best carb ever designed and will deliver fuel injected mileage when properly built. They will also spank a Holley on the dyno when properly prepared.
www.jimboscarbs.com
FWIW, Jim
Advanced
Joined: Jun 2010
Posts: 95
Likes: 77
We test every carburetor prepared here on a real test engine. We also build them exactly for the application they are going to be used on.
I put a few "basic" calibrations in our book, to help guide folks who decide to do their own work. We back up the information in our book with the best parts currently available for the Quadrajet carburetor.
These days it is quite rare to find anything completely "stock" anymore. One must consider that when you make changes to the engine and drivetrain, the carburetor is being asked to work outside of the calibration it was originally designed for.
The Q-jet is simply amazing at being able to adapt to varying engine combinations, but every single one was application specific, so they will need some help in one or more areas to work perfectly when used outside the original application.
To compound the problems of being application specific, modern fuels do not have the same specific gravity and BTU content of older fuels that these carburetors were originally set-up for. I remember back in the 70's if you spilled some gas on the workbench it would stink for days, now if you walk out of the room to take a phone call, then come back in a few minutes, it's GONE!
Since we street, dyno and track test everything, I get to do a LOT of testing/tuning with a variety of vehicles. We work very closely with our customers, and supply a LOT of "Pure Stock", FAST, and legal Stock and Super Stock carburetors and tuning parts to scores of customers.
I also race my daily driver as often as I can find my way to the track. Using all the feedback and input I get from all sources, it only helps us to better the product.
Kind of a neat email we had sent to us just before Christmas, thought I share it here. The history behind the email is that it is from a repeat customer, and he prepared his new engine mentioned in the email as basically a duplicate of the engine that powers my Ventura. The only real difference is the compression ratio, my engine is a true 11 to 1 static compression, his is closer to 10.5 to 1.
I would also mention that the dyno shop owner was an "old timer", who gave him some grief showing up with a dual plane intake on his new engine with a Quadrajet sitting on it. He told him that over the years he's seen plenty of them show up, and he always ends up getting out his custom tuned Holley so they can make some real power on the dyno.
Anyhow, here's the email:
"Hi Cliff,
I thought you might like a picture of one of your beautiful carbs sitting on this nasty 468. Twas the night before the dyno session and all thru the house, not a creature was stirring...
And the next day on the last and best two pulls, peak tq. was 604 ft.lbs.at 3900 rpm, and the best hp pull was 552 at 5500 rpm. SD ported KRE heads flowing around 297 cfm, RPM intake, SD Old Faithful cam, 10.5:1 cr., crank scraper, 30 degrees total timing, and Cliff's 800 cfm q-jet.
There were a couple of other brand boys there that were so shocked, I thought we were going to have to dial 911.
The dyno guy walked out into the shop and says...604 ft. lbs. with a Q-Jet, can you believe it ???!!! The only thing we had to do to the carb was adjust the idle speed and lean the APT 1/4 turn! Thanks Cliff!!!"
Anyhow, thanks for the kind words here, and I apologize for not being able to spend more time on this website in the Tech Forums helping folks out. We are months behind in the shop, and I'm down to contributing to one or two Forums each day.
I would encourage anyone with Tech stuff, problems, etc to visit our website. I answer all threads and all PM's, plus any correspondence sent to my email address......Cliff
http://www.cliffshighperformance.com/
I put a few "basic" calibrations in our book, to help guide folks who decide to do their own work. We back up the information in our book with the best parts currently available for the Quadrajet carburetor.
These days it is quite rare to find anything completely "stock" anymore. One must consider that when you make changes to the engine and drivetrain, the carburetor is being asked to work outside of the calibration it was originally designed for.
The Q-jet is simply amazing at being able to adapt to varying engine combinations, but every single one was application specific, so they will need some help in one or more areas to work perfectly when used outside the original application.
To compound the problems of being application specific, modern fuels do not have the same specific gravity and BTU content of older fuels that these carburetors were originally set-up for. I remember back in the 70's if you spilled some gas on the workbench it would stink for days, now if you walk out of the room to take a phone call, then come back in a few minutes, it's GONE!
Since we street, dyno and track test everything, I get to do a LOT of testing/tuning with a variety of vehicles. We work very closely with our customers, and supply a LOT of "Pure Stock", FAST, and legal Stock and Super Stock carburetors and tuning parts to scores of customers.
I also race my daily driver as often as I can find my way to the track. Using all the feedback and input I get from all sources, it only helps us to better the product.
Kind of a neat email we had sent to us just before Christmas, thought I share it here. The history behind the email is that it is from a repeat customer, and he prepared his new engine mentioned in the email as basically a duplicate of the engine that powers my Ventura. The only real difference is the compression ratio, my engine is a true 11 to 1 static compression, his is closer to 10.5 to 1.
I would also mention that the dyno shop owner was an "old timer", who gave him some grief showing up with a dual plane intake on his new engine with a Quadrajet sitting on it. He told him that over the years he's seen plenty of them show up, and he always ends up getting out his custom tuned Holley so they can make some real power on the dyno.
Anyhow, here's the email:
"Hi Cliff,
I thought you might like a picture of one of your beautiful carbs sitting on this nasty 468. Twas the night before the dyno session and all thru the house, not a creature was stirring...
And the next day on the last and best two pulls, peak tq. was 604 ft.lbs.at 3900 rpm, and the best hp pull was 552 at 5500 rpm. SD ported KRE heads flowing around 297 cfm, RPM intake, SD Old Faithful cam, 10.5:1 cr., crank scraper, 30 degrees total timing, and Cliff's 800 cfm q-jet.
There were a couple of other brand boys there that were so shocked, I thought we were going to have to dial 911.
The dyno guy walked out into the shop and says...604 ft. lbs. with a Q-Jet, can you believe it ???!!! The only thing we had to do to the carb was adjust the idle speed and lean the APT 1/4 turn! Thanks Cliff!!!"
Anyhow, thanks for the kind words here, and I apologize for not being able to spend more time on this website in the Tech Forums helping folks out. We are months behind in the shop, and I'm down to contributing to one or two Forums each day.
I would encourage anyone with Tech stuff, problems, etc to visit our website. I answer all threads and all PM's, plus any correspondence sent to my email address......Cliff
http://www.cliffshighperformance.com/
