Rochester Quadrajet ?

[likaroc13]

hey guys,

last weekend the PO brought some of the additional parts that came with my '66 pickup...i got the original 283, extra Powerpack heads, & a Rochester Quadrajet...from running the numbers i have concluded that it's a 1985 model (#17085227) Quadrajet...how would i figure CFM?

also, i currently have no use for this since my truck has a relatively new Edelbrock 600 carb...but i could possibly use it in the future when i rebuild the 283...i was thinking of putting the 283 in a '66 Burb....but is it worth it to keep the Rochester, or should i get rid of it (opinions, please)?

thanks for any info/suggestions

[19GMC63]

a large majority of them were around 750cfm I believe. Only other information I could find was that carb was used in Chevys and GMCs from 80 to 88, and had an electric choke.

I say it depends on if you wanna fiddle with tuning a Q-jet since they aren't as easy to tune as the edelbrocks. Some people swear by a properly tuned Q-jet. Also, wIth the smaller primaries, you may get better economy with the Q-jet, plus everyone and their brother runs those Edelbrocks/Carter AFBs (me included).

[BMSJaX]

Diddo on the 750 cfm. I am running a summit rebuild that I got for dirt cheap and it out performs the Holley I had big time. I noticed better throttle response, pickup and power right away and my MPG went from 9-10 to 12-15. It is a picky carb and likes things its way. But it only took me about a week of internet research and playin around to get to understand how it works pretty well. Its worth playin with.

[66GMC-Canuck]

Another ditto on the Qjet. Awesome carb. You can tune the heck out these carbs and once you get the hang of it they are easy to work on. You can get jet kits for them from Jegs I think.

[Winola73]

There were 2 sizes of QuadraJet, 750 cfm and 800 cfm. Yours will be a 750 but don't worry about it being too big, it will only flow what your engine can pull through it. GM used them on everything from 231cid V-6's to 500 cid V-8's including the Buick 455 Stage 1. The 455 through 500 V-8's got the 800cfm. Ford also used them on some of their CobraJet engines in the early 70's and Chrysler used them on their small V-8's in the 80's.

The Q-Jet is very sophisticated and it's the next best thing to fuel injection if you give it the respect it deserves. Get a copy of Rochester Carburetors by Doug Roe and Rochester QuadraJet Carburetors by Cliff Ruggles before trying to tune one. It may seem a little overwhelming at first but once you get the hang of it and get one really dialed in you'll love them.

From the model number your's is probably off an '85 truck with a V-8 and manual transmission. If you're lucky it is the M4ME non-computer controlled model and not the E4ME electronic carb. There's not a lot you can do with the E4ME but the M4ME is one of the best QJ's you can get for a street application. The E4ME will have an electrical connection on the top of the carb body next to the accelerator pump, the M4ME will just have a "bump" in the casting.

[62 mark]

gotta love the quadrajet...when we were young'ns, it was the easiest and cheapest bolt on power add-on. can't beat the sound of those big secondaries opening up...WAAAOOOOOOOOOOOOOP!!

[BMSJaX]

Originally Posted by 62 mark

gotta love the quadrajet...when we were young'ns, it was the easiest and cheapest bolt on power add-on. can't beat the sound of those big secondaries opening up...WAAAOOOOOOOOOOOOOP!!

This is true! I love the sound when I open it up! Everyone gives a WTF does he have under there look!

[Corts60]

I agree with all above...keep the Q-jet!

[truckdrivinsob]

I love my q-jets so much i dumped a new edelbrock for one ! That sound can make a grown man very very happy !

[66GMC-Canuck]

I have run QJets since the early 80's once they are dialed in you don't have to touch them. Love those carbs.

[poncho_villa]

Absolutely agree with the above. The throttle shafts on my Q-jet were starting to leak from years of service, so I bought a new stage 2 from Jet performance. No regrets. Keep the Q-jet.

[likaroc13]

thanks for all the input....based on responses, it sounds like i need to keep this Q-jet & install it in place of my Edelbrock

[Corts60]

good choice. Also, if you find that the throttle shafts start getting loose and causing a lean condition, they make bushings kits for them....

[likaroc13]

hey guys, can I keep the Edelbrock Performer intake with the Quadrajet setup, or will i need to switch to something else? if switching, what do you recommend?

thanks

[66GMC-Canuck]

I am running the Edlebrock Performer Air Gap intake with my Qjet. Runs sweet and sounds awesome when you kick down and all 4 barrels are sucking air.

[likaroc13]

Originally Posted by 66GMC-Canuck

I am running the Edlebrock Performer Air Gap intake with my Qjet. Runs sweet and sounds awesome when you kick down and all 4 barrels are sucking air.

is your engine basically stock or modified? right now mine has the polished Edelbrock Performer intake...i plan on switching to the natural finish though...but my engine is a pretty stock 327, so i don't wanna go overkill on anything...would the Air Gap be overkill vs. the Performer?

[66GMC-Canuck]

Mines a pretty stock 350. I like the Air Gap as it's built for the Qjet and it has the gap that allows the mixture to run cooler. Its not polished its natural and it seems to run really nice with my 750 CFM Qjet. I got it dialed in nicely. Cruising you are running on the front two when you stomp it, it screams. So for me its mild but when I need to it moves my 66 down the road as fast as I am happy with. Mainly she's my work truck and cruiser.

So in my opinion not overkill and you can't beat the look.

[muddpile]

I have some friends swear by them, where as I myself swore at them as every one I've ever had the secondaries never worked right, and the throttle shafts were worn. That being said, I never took the time to rebuild one or fix the throttle shafts. I switched to Edelbrock, but they aren't that great either, especially in terms of fuel economy. Are these rebuild parts readily available?

[66GMC-Canuck]

Yes you can get everything for them for rebuilds. A couple of sites have all the parts listed plus JEGGS sells the street and strip Jet kit for them. I just rebuilt the one on my truck and I am rebuilding another as backup plus converting it to electric choke. Pretty sweet, a guy sold me 2 for $25 said he does not like them. I laughed I love these carbs been using them for over 20 years. Had one on my Buick 455 Stage 1 beauty of a carb. Rock solid when you dial them in right.

[likaroc13]

Originally Posted by 66GMC-Canuck

Mines a pretty stock 350. I like the Air Gap as it's built for the Qjet and it has the gap that allows the mixture to run cooler. Its not polished its natural and it seems to run really nice with my 750 CFM Qjet. I got it dialed in nicely. Cruising you are running on the front two when you stomp it, it screams. So for me its mild but when I need to it moves my 66 down the road as fast as I am happy with. Mainly she's my work truck and cruiser.

So in my opinion not overkill and you can't beat the look.

thanks for the info...i'll look into the Air Gap