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 Qjet for daily 454 
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Joined: Fri Feb 08, 2013 2:37 pm
Posts: 1704
The single bleed carbs are goofy enough, but if the bleed is larger than .052" ..... eh.... Somebody out there in carburetor land is drilling the single bleed to large .080"++ sizes and with that scheme I have seen engine damage result in a heavy rig towing application, 350 in a Suburban. I don't care much for the single bleed, but they work OK converted to dual .046" bleeds to mimic the early carbs with one on top and one on the side of the nozzle well (with the single bleed plugged).


Mon Apr 10, 2017 4:39 pm
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Joined: Wed Oct 23, 2013 8:01 am
Posts: 108
Thanks to Tuner I've had good luck with SMAB that I converted to DMAB. It's not used for towing, just making black stripes.


Mon Apr 10, 2017 6:15 pm
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Joined: Fri Feb 08, 2013 2:37 pm
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As near as I can tell with chassis dyno, data logging and seat of the pants, when they are changed to dual bleed configuration they act like a normal old-school QJet.


Mon Apr 10, 2017 6:21 pm
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Joined: Tue Aug 23, 2016 10:38 am
Posts: 84
I did put on the smab carb just to get the car moving. The single is fat, like expected. I am also slowly converting a edelbrock qjet too dmab that will be replacing the current carb.


Fri Jun 16, 2017 7:38 am
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Joined: Tue Aug 23, 2016 10:38 am
Posts: 84
So I was wrong. While initially driving with the 72 jet it seemed pretty good on my drive but when lean (like 20s on the wide band with misfires) so I figured maybe the rods hadn't seated or something. I of course over corrected thinking is must be super lean going to 76s and worked all the way back to 72s after finding one of the idle jet restrictions had a plug. Now it runs 14.5-14.8 cruising and in the 12s wot. I ordered some 71 jets to see if I can get it into the 15.5-16s. Of course this is just driving and looking at a wide band.

I just was trying to get this carb to work OK, till I have time to build the other carb.


Wed Jun 21, 2017 12:02 pm
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Joined: Fri Oct 23, 2015 8:43 am
Posts: 33
One of these days I will get around to building a DMAB carb to replace my current SMAB carb. Just need to find the time.

My current SMAB carb works very well at WOT, and even low speed cruise, but tends to go rich at cruise as rpms increase. Haven't been able to "cure" this with the SMAB Q-jet.


Wed Jun 21, 2017 1:36 pm
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Joined: Tue Aug 23, 2016 10:38 am
Posts: 84
Actually it physically runs pretty decent but I haven't driven it very far yet. The secondary activation with the truck style lever causes the tires to lose traction at anything below 15 mph.


Wed Jun 21, 2017 2:24 pm
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Joined: Fri Feb 08, 2013 2:37 pm
Posts: 1704
QJets rule. Carry on.


Sat Jun 24, 2017 1:06 pm
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