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« Last post by DJD OLDS 4MC on January 29, 2026, 05:58:52 PM »
Greetings, Cliff and fellow forum members!
My son and I are new to this forum and going forward, we hope answers to the questions we post will contribute positively to the excellent knowledge base we’ve found this forum to provide.
Firstly, we’d like to acknowledge and thank Cliff Ruggles for his willing helpfulness and dedication to providing, through this forum, the free exchange of Quadrajet knowledge. We found his book, How to Build and Modify Quadrajet Carburetors to be an excellent treasure trove of information, and an invaluable resource. Looking forward to a new edition where he might share more information on tuning using air bleeds.
Over the past 50 years, I’ve built, modified, tested and then rebuilt many Olds Quadrajets. Currently, in my carb corral I have four of these ahead-of-it’s-time analog technological marvels that I’ve used as test-mules in my long term search for the perfect performance recipe using hit-or-miss tuning with early O2 sensor technology which was better than just reading spark plugs and looking at carbon buildup in tail pipes.
Last year, with my son’s help, we upgraded to an Innovate DLG-1 gauge and LC-2 controller, a pair of wideband oxygen sensors, and an Innovate PL-1 data logger.
While going down the road, the realtime AFR data displayed by the DLG-1 from both sides of the exhaust at the same time is remarkable and represents a giant leap forward from the old K&N flashing led lights. After logging our test runs, we’re able to go back and review how the changes we made affected the AFR numbers relative to rpm, manifold vacuum, changing terrain, and over time.
This summer, we hope to use that technology and the advice and information we gain from this forum to dial-in a Quadrajet 4MC #7040251 for installation on the 463 Olds V8 we built last year and installed into a 1980 Olds Cutlass Supreme which functions as a daily driver.
Last century, reading spark plugs, looking at carbon buildup in tail pipes, searching for printed text, staring at flashing leds, and relying on past experience were the only resources I had available in developing recipes for the Quadrajet.
Today, with your help Cliff and/or some the other ‘in the know’ forum members, we’re hoping to bring to a close, my long term search for the perfect performance recipe.
Any setup advice offered will be very much appreciated.
Thanks.
DJ & Son (Jed)
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