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 Q-jet selection 
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Joined: Tue Aug 23, 2016 10:38 am
Posts: 84
I am planning to add a q-jet to my 350 in my car this winter. I am looking for a good starting model. I have a couple of later SMAB carb and a nice edelbrock 795 q-jet but I was hoping to save that for when I install the 496.

My buddies are engine machinist and they buy 350 cores by the truck load to rebuild for local dirt track racing. They have a pile of 20+ qjets and will sell me as many as I want cheap, since the pile never gets any smaller.

The car is my daily right now with a low mileage l-65 (2bbl 350) 8.5 to 1 smogger. This winter it will be getting a performer intake, q-jet, 214/224 cam, headers, duals and 3.23 gears. Pretty mild nearly stock combo. The cam could cause a bit of vac loss at idle but it should still be in the 12-15 in/hg range. Of course the q-jet is perfect for this allowing great mpg and the performance when called upon.

I am not completely new to q-jets and honestly after dyno tuning my 454 K30, I completely changed my mind about q-jets.

I am hoping to use this as a learning experiment so when I finish the big block I will be better able to adjust for mpg and performance in a more radical application.

I assume the post 76 models with the top APT is what I am looking for but can you guys help me narrow it down?


Wed Sep 07, 2016 5:24 pm
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Joined: Fri Feb 08, 2013 2:37 pm
Posts: 1702
I prefer the type with two main well bleeds in the primary. I use those or modify the single bleed to have .046" bleeds located similar to the dual bleed and plug the original over the nozzle. If you can use a divorced choke, the 1969 carbs are the best, but once you start modifying everything it doesn't make much difference what you start with. Throttle linkage, vacuum ports and choke type are important to consider to avoid a lot of screwing around.

(Tell your buddy with the cores he's my new best friend..!!.. If he knew how well a QJet works on the oval, particularly on dirt where a good driver spends a lot of time twitching the throttle at mid-pedal to control the drift in the corner, he wouldn't let you have a single one. )


Wed Sep 07, 2016 5:36 pm
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Joined: Tue Aug 23, 2016 10:38 am
Posts: 84
so is there a specific range for those carbs or do I need to just look at each one? I guess it wouldn't kill me to look at each one, just wondering.


Wed Sep 07, 2016 5:41 pm
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Joined: Tue Aug 23, 2016 10:38 am
Posts: 84
Also since you are offering the advice and have this great site, where do you suggest I purchase parts? I want to build a little tuning kit like edelbrock used to sell for there performer rpm q-jet so at least the basic hard parts are at hand when tuning.


Wed Sep 07, 2016 5:45 pm
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Joined: Fri Feb 08, 2013 2:37 pm
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Get the whole bone pile. That will give you a selection of parts and you are going to need more cores anyway, when people see how yours works.


Wed Sep 07, 2016 5:49 pm
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Joined: Tue Aug 23, 2016 10:38 am
Posts: 84
Well I had a quick min before work to look at a few carbs and grabbed 3 numbers
7045203 75 truck 350 manual?
17057204 77 truck 350 auto?
17059226 79 truck 350 auto?

I am still working on where each air bleed is etc but at least the first 2 have a large hole in center of the base of booster. Not to the side like were some of you are drilling the second main air bleed. Not sure if this is good or bad though I do remember a picture of it in the ROE book next to a similar hole with a brass insert. I guess my mind isn't what it used to be.

Figured I would buy 4 or so carbs to start with.


Fri Sep 09, 2016 8:13 am
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Joined: Wed Oct 23, 2013 8:01 am
Posts: 108
How much did you pay? Never can have too many Qjets laying around.


Fri Sep 09, 2016 11:26 am
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Joined: Tue Aug 23, 2016 10:38 am
Posts: 84
I didn't get any yet but will pick them up after work. 4 for $50. He has plenty of the early carbs with the lower apt 70*****?, I guess I was mostly looking at the 170 carbs. Are all the 70 carbs divorced choke?


Fri Sep 09, 2016 11:37 am
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Joined: Fri Oct 23, 2015 8:43 am
Posts: 33
77cruiser wrote:
How much did you pay? Never can have too many Qjets laying around.


+1

They aren't making any more, and good cores that haven't been butchered are getting a little scarce. 15 years ago, they were practically free.


Fri Sep 09, 2016 3:06 pm
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