Quadrajet Carbs

[John Marinan]

There's been a spirited exchange concerning Quadrajets lately.
Her's some sources that may help take the mystery out of the Quadrajet.
The Guru of the Quadrajet carb is Cliff Ruggles.
His book is How To Rebuild and Modify Rochester Quadrajet Carbs.
The cost is $24.95
Just google Cliff Ruggles or call 740 397 2921
There is another Quadrajet source for parts and complete units, Carb Junkies, they're on the web.

 

[barronj]

Ever heard of blueprinting a quadrajet? I have a friend who does it, allegedly. I have no reason to doubt him, as he's a cam designer/engine builder, focussing on drag boats & circle track cars.

 

[nvrstuk]

q jet

People rag on Qjets because they don't understand them. People literally whine because an engine won't idle well with a qjet on it. These same folks will spend days or weeks finding parts, researching how to install EFI, spend $500-1500 and up to install EFI. Many then have to post problems on diagnosing codes or symptoms on problems they can't figure out on their EFI but they HATE Q-jets!!! HAHAHAHA. Not saying q-jets are better than EFI, just saying that if you're biased you are BIASED. No way to get out of it. It's soooo freakin' funny to read the posts about how great EFI is, it never causes any problems but there are so many posts on dealing with EFI symptoms just like anything else. Fun to read 'cause the same guys that won't spend $250 on a professional, quality built q-jet will spend that much on just a new gas tank to support EFI. Wow...

 

[Ranchtruck]

Q-jets are nice carbs, however there is a lot going on in one, and a lot to screw up if you start adjusting things willy nilly.

One thread recently had someone giving directions on how to adjust the secondary air flap tension, when the complaint was stumbling when getting on the throttle. The secondaries don't come into play until it's completely floored and the engine is revved up. A stumble when you first get on it is always an issue with the primaries. So it's hard to get good advice on how to set one up and not get confused by all the random "tuning tips" that will probably just make it run worse.

You need to understand how each circuit in the carb works before you start messing with it. GM ran the same carb on engines from 4.5-8.2l, so there's a lot of adjustability built in. Setting one up wrong is easy. They can be excellent when set up by someone who understands how they work.