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AFB jet size?
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raysinvegas View Drop Down
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    Posted: May/08/2012 at 11:50pm
Running a stock 290 2bbl with a stock 4bbl manifold and an AFB on top. Headers and glasspacks. What should the jet size be? I'm using Edelbrock jets from the 1406 calibration kit.
Andy Ray
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Points: 2692 		Post Options Post Options   Thanks (0) Thanks(0)   Quote tsanchez Quote  Post ReplyReply Direct Link To This Post Posted: May/09/2012 at 12:13am
What carb


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Points: 1620 		Post Options Post Options   Thanks (0) Thanks(0)   Quote raysinvegas Quote  Post ReplyReply Direct Link To This Post Posted: May/09/2012 at 1:34am
Carter AFB 4468S
Andy Ray
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Points: 1040 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 70amxvegas Quote  Post ReplyReply Direct Link To This Post Posted: May/09/2012 at 1:55am
I have a holley  650 dp on my work bench,

Edited by 70amxvegas - May/09/2012 at 1:56am
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Points: 6359 		Post Options Post Options   Thanks (0) Thanks(0)   Quote FuzzFace2 Quote  Post ReplyReply Direct Link To This Post Posted: May/09/2012 at 9:47am
What do the plugs look like after a 20 mile hiway run. And I dont mean on the hiway for 2 miles and 18 to get there. Also you cant drive it off the hiway or it will throw off the plug readings.
Once you have the readings you then need to know the jet size of what the carb you have now is then yuo can make any changes based on that.
How many will have a stock 290 with that carb setup to say I use xxx jet?
My .02
Dave ----
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Auto or manual?
 
what is in it now?


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I'll have to check the numbers when I get off work. You need a freakin' microscope to read them!
Andy Ray
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290/auto
Primary jets are marked 498. I think that means they are .198"?
 
The car has always run VERY rich, but well. Plugs are carbon covered. Black smoke out the tail pipes.
Primary mixture screw is out 1/2 turn. I can close it all the way and it still runs rich.
Andy Ray
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Points: 2608 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 69 ambassador 390 Quote  Post ReplyReply Direct Link To This Post Posted: May/09/2012 at 9:08pm
Thats not a primary mixture screw, it's an idle mixture screw.  The primary metering rods and step up springs control the mixture off idle.  You need to step up on the metering rods to ones that fill more of the jet at cruise.  Measure the thicker part that rides in the jet and get eldelbrock ones that are close to that size but a bit larger.  Try to keep the change to a little at a time.  You only need to step up jets if you cannot get there with the rods.  Also take a vac. reading in gear at isle and warmed up.  If the springs are too heavy, they will cause this richness.  Try lighter springs. Get a tuning kit for a 1406 carb.
Steve Brown

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Points: 2692 		Post Options Post Options   Thanks (0) Thanks(0)   Quote tsanchez Quote  Post ReplyReply Direct Link To This Post Posted: May/09/2012 at 9:47pm
Tell me what size the metering rods are, that jet size it too big for anything


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