New quadrajet set up
New air-gap manifold and custom/rebuilt q-jet. Sounds good but I still need to set the timing on the distributor and the carb is tuned already. Hope you like, nothing to fancy just a few revs and walk around...the Exhaust is true dual no x/h pipe and it has cherry bomb glasspacks(3 inch)
how to minimize engine bog with a Quadrajet carb
this is to minimize engine bog when the pedal is to the metal. do not over tighten, very small spring...you want to try 1/4 turns or 1/2...q-jets are good if tuned properly. also when you are tightening screw it will have tension on it so keep the screwdriver firm. 1986 gmc sierra single straightpipe to cherrybomb. you will need a small flathead screwdriver and a 3/32 allen key. be sure not to tighten to much or else your vacuum secondary flaps wont open.
Issues with my thermoquad rebuild. Instruction sheet doesn't quite match the carb, which it never does....
Lovely Induction Roar as the Quadrajet Secondaries tip in
How to debog your Quadrajet part 3
In the first two videos we looked at operational theory of the Quadrajet. In this episode we'll explore a couple mistakes the home mechanic often makes in an effort to improve the performance of this unit.
Identifying vacuum ports, late-style Quadrajet
I always see a lot of questions about what various vacuum ports do on a Quadrajet.
Here's a general guide that will point you in the right direction. Remember that there were many different Qjets over the years and vacuum port locations and number will vary. This video is representative of 1975-90 carbs.
More Quadrajet tuning, some things! Part two in this Saga Sept 13, 2010
With the camera sitting on the oil filler cap a few more things to show how a metering rod system works on a carburetor. The car has a slight stumble and surge at a light throttle cruise at about 55 to 60 MPH. By swapping out the .050 metering rods to .048 units, the stumble and driveability concerns are now gone. Going richer would mean worse fuel mileage one may think? No! Now that the mixture is right, LESS throttle opening is needed now, which means higher vacuum, and this way the metering rods will block off the correct amount of fuel, and in the proper timing and percentages, so the car runs much smoother. As stated many times, patience and reading up on, and understanding how these intricate carburetors work will help out very much! Enjoy!
Pontiac 400 idling on dyno right after break in session
A Pontiac 400 bored .030" over so now a 406 with comp cams extreme energy hydraulic cam and lifters, roller timing chain and roller rockers. Lightened and balanced Scat crank. Ignition upgraded to MSD HEI with Accel 8.8 mm sprial core wires. 6X-4 heads ported and port matched to ported factory dual plane intake manifold. Factory 750 CFM Quadrajet reworked by Cliff Ruggles performance.
not such a top speed run, moreso enjoyin the higher rpms / shift
A 79 chevy C-30 dually pickup w/ 454 V8
Here is a friend of ours chevy pickup. I've been told it's a 79. It has a 454 big block V8, a turbo 400 3 speed direct automatic, and dual Exhaust which i don't know who makes the mufflers. We changed the carburetor to a edelbrock 4 barrel in place of the quadrapuke (quadrajet) carburetor. Quadrajets are good carbs but when they go bad, they're bad. The quadrajet on this was really bad, the throttle bushings were worn on it and it when the secondaries opens up i'm assuming it just dumps fuel like crazy because when we floored the gas it was like pop pop braaaaaap. With the old carb on it used a quarter tank of gas to drive 10 or 15 miles.
How to de-bog your Quadrajet part 1
Sorry guys, I got the videos a bit out of order.
The Rochester Quadrajet has gotten a bad rap over the years, often called a Quadrabog or Quadrajunk.
In fact, this is a great multipurpose carbureter once you understand how they work and what not to do to them.
In this clip I introduce you to the Quadrajet and begin explaining the theory of operation of these units.
750 vs. 800cfm Rochester Quadrajets-how to tell them apart
There exists a ton of misinformation regarding the actual airflow capacity of the Rochester Quadrajet. Not many people know how many variations there are or how to tell them apart.
Here is a simple video explaining how to identify each size based on casting design. I will cover the "cfm-limited" carbs in a separate video.