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 Post-'80 truck carbs 
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Joined: Mon Dec 29, 2014 1:26 am
Posts: 433
I have two truck carbs here, 17080213 & 17088041. Both have the primary main bleed hanging out over the center of the booster.

The 8041 has the extra adjustable air bleed on the secondaries - what's the proper way to delete that, plug the up-channel in the base of the bowl casting (so the cover & screw can be left as-is)?

The pri main bleed on the 0213 is .052", but on the 8041 it's HUGE, around .088". The 8041 has obviously been rebuilt (& the 0213 has obviously not been, zero evidence anywhere it ever even had the lid off since new), and I'm not convinced these bleeds haven't been drilled out. Should I just calibrate both carbs the same? Put a .052" bleed in the 8041?

Anything else peculiar about these last-gen carbs I need to know?

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Fri Jun 05, 2015 3:59 pm
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Joined: Mon Dec 29, 2014 1:26 am
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What's this thing in the 17088041, limiter for the upper height of the PP? And something I've not seen before, a steel bushing at the pump shaft hole (factory installed).

Image

Closeup of the (mutilated?) main bleed.

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Fri Jun 05, 2015 4:21 pm
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Joined: Sat Mar 29, 2014 10:27 am
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Those carbs are referred to as Single Main Airbleed (SMAB). They were the last gasp of Qjets to meet emissions regs. I believe they first came out in 1977 trucks. To my knowledge, the 77 thru 81 truck carbs usually had the smaller main air bleed(.052). My 82 truck carb is .086. The 80's carbs used the .036 tip primary rods that only went from .048 to .054. My 82 carb has the steel pump bushing. I've run my 82 carb with either 76 or 77 main jets with .052 primary rod. Edelbrock based the design of their "850" model 1910 Qjet on the SMAB. The only info I have is for the 17080213. 72 main jets, .050 primary rods DP secondary rods.


Fri Jun 05, 2015 5:40 pm
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Joined: Mon Dec 29, 2014 1:26 am
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I found 73 jet, 49V pri rod, DP sec rod, 'L' hanger in the 0213. 8041 had 75 jet, 61S pri rod, EK sec rod, & 'H' hanger.

Relocating the idle bleed from the wall to the lid still works OK with these castings? Looks like it'd be a tight squeeze, if I have the location right.

Image

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Fri Jun 05, 2015 7:38 pm
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Joined: Sat Mar 29, 2014 10:27 am
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Here's what mine looks like. I haven't tried it out on the car yet. My current Qjet runs so damm good I'm hesitant to touch it!


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Fri Jun 05, 2015 8:31 pm
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Joined: Mon Dec 29, 2014 1:26 am
Posts: 433
That helps... I's a bit skeered about drilling the top, you don't know absolutely for sure where the hole will come out until after it's done.

I've already done the idle tubes & IDCRs and plugged the hole in the wall.

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Making new idle tubes is easier than I thought it would be, pics in my Holley 4011 thread starting on page 6. I have seen other Qjet people asking/looking for smaller sizes than what's available for sale anywhere, but anybody capable of pulling the old ones out would be able to make new ones from scratch without much trouble. Link to p6: viewtopic.php?f=25&t=775&start=50

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Fri Jun 05, 2015 9:17 pm
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Joined: Sat Mar 29, 2014 10:27 am
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If you flip the lid over, the holes are partially drilled already. All I do is drill them thru to the top. If drilling freehand, keep the drill straight or make a fixture for a drill press. Nice job on the idle tubes!


Fri Jun 05, 2015 9:50 pm
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Joined: Mon Dec 29, 2014 1:26 am
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tuner wrote:
Drill 4 x .024” holes in each tube.


Don't you love the way he says things like that? Holy hell, I think I'd rather be kicked in the b@lls than have to do this part again! :\'(

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Sat Jun 06, 2015 1:13 am
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Joined: Wed Oct 23, 2013 8:01 am
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I made this little fixture for drilling tubes. Not very fancy but it does the job.


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Sat Jun 06, 2015 9:52 am
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Joined: Mon Dec 29, 2014 1:26 am
Posts: 433
I found it goes a little easier when not using a drill that looks like this:

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Sat Jun 06, 2015 3:42 pm
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