The car starts up, engine warms up, it idles smoothly around 850-900 rpms. However the A/F guage reads rich as well as my plugs. Not really rich, but enough to drop my MPG down a bit and hurt performance IMO.

If I screw in the idle air bleed screws (one on each side of the metering plate... right) any more then 2 full turns out, the idle goes to crap. My float level is fine on both the primary and secondary bowls. My fuel psi is about 6-7psi.

Again, it idles fine and I get no bog even under hard acceleration (most times). It's just that this thing runs high normal/rich when I idle and at cruise speeds. How can I drop this down to high/mid normal range? Jet changes will not do this... right? I am at #68 primary jets now.


Holley 750vac secondary...

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

Bio, have you looked at the power valve? You may need an alternate power valve or just a new one. For the idle mixture, are the primary blades open too far thus uncovering the transition circuit slot? If so you can adjust the secondary blades to be open slightly at idle or drill small holes in the primary blades. I think they say start with 0.050-0.070" holes to get more air in at idle when using large cams. What cam are you running? It is hard to imagine that this would be necessary on a mild small block though.

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350 Vortec, forged flat-tops, CompCams XE268, Edlebrock RPM, Holley 3310, TH350 w/Holeshot 2400, 3.23 posi, Heddman shorties, HEI

 

Well Eric, I'm basically running a very similar cam to yours. My idle quality is fine, it is just rich.

Would a blown power valve cause a rich idle/cruise? I guess it could, but the carb has always run this way since I put it on (fresh out of the box from Holley) a few months ago.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

I think a blown power valve will cause the rich idle/cruise condition although I haven't experienced it. If it that new then I wouldn't expect the PV is blown either, it probably wouldn't run decent at all. Hopefully someone will post some more possibilities.

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350 Vortec, forged flat-tops, CompCams XE268, Edlebrock RPM, Holley 3310, TH350 w/Holeshot 2400, 3.23 posi, Heddman shorties, HEI

 

Jets WILL NOT change your idle or cruise mixture.

2 turns is probably too much....and it should still run fine if you screw them in more. Try pulling out the screws and blasting a goodly amount of carb cleaner through there. Just be careful you don't get it in your eyes when it shoots out the idle bleeds in the top. Then put the screws back in and start at 1 turn. Change the idle speed screw if you have to.

And for god sakes check your^%#$^# powervalve already..you've been saying that for like 5 posts on the subject

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"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports

 

I'll try hitting the idle screws with some carb cleaner (thanks for the concern for my eyes Jester ). Maybe I'll take a look at the powervalve... do you think that may be a problem? IIRC, it had a 6.5 stamped on there.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-