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.

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Decoding a Rochester Quadrajet part 1: The name
Rochester Quadrajets tend to mystify people because of the various model names assigned to them by GM. Add to that a redesign in the '70s and the confusion only grows. In this video we'll learn the different model names and also how to differentiate between early and later-model Qjets. Enjoy!





Identifying Quadrajet vacuum ports
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. Enjoy!





How to diagnose a Quadrajet part 1
I get lots of questions about poor running issues. Here's how to check them out.




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