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.
Identifying vacuum ports, late-style Quadrajet
I always see a lot of questions about what various vacuum ports do on a
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
How to identify 4 barrel carburetors
Here's a guide to help identify the most common 4bbl carbs including
Edelbrock, Quadrajet, Holley and Thermoquad.
There are a few older or more obsolete carbs not shown including Rochester
4G, Autolite-Motorcraft 4100/4300/4350 and Carter WCFB that I'll detail in
the future provided I can actually find one.
More Quadrajet tuning, some things! Part one in this saga on Sept 13, 2010
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!
Most relaxing sound for men - Old-School American V8 Corvette C3 1979 (Stingray)
Includes Cold engine idle, warm idle and a bit of revving to about 4500
RPM. I decided to create this video since my Vette now sounds quite loud
thanks to the Cherrybomb glasspack Exhaust and removal of the catalyst. The Exhaust is basically stock. I think this is
one of the most relaxing sounds for men who are into cars and machines :)
Engine: 5.7 L (350 cid) V8 L-48
Transmission: Warner 4-Speed Manual
My Corvette is generally in very good condition and it has already been
restored once in USA some years before it arrived in our country. I got the
car in a state where the exterior + drivetrain were fine, but the interior
needed new carpet, some painting and several other components in order to
look great. I'm now pretty much done with the interior. The engine used to
have issues but those were mostly external (bad thermostat housing, bad
spark plug wires etc.). By now the engine is a pleasure to drive, but the
Rochester Quadrajet carburetor has hard time keeping the pre-selected idle
speed and sometimes wants to hold it higher, then lower. It might be also
some extra fuel leaking in from somewhere occasionally. There used to be
some vacuum leaks but I've taken care of them. Perhaps I will replace the
intake + carb with an Edelbrock setup for next driving season. The engine
compression has been measured recently and the results were perfect for all
NB! We will soon try to film the Vette from another car when driving on a
motorway. I'm hoping to get some good footage that way.
For more information and work history on my Corvette, Suburban and ex-Jeep
Grand Cherokee, please visit my blog at http://www.georgescarblog.com .