Just keeps wanting more fuel but why?

[Chryco Psycho]

If covering the carbs with your hands brings up the RPM it is obviously lean so I doubt you will fix it with the ign system

[1 Wild R/T]

If covering the carbs with your hands brings up the RPM it is obviously lean so I doubt you will fix it with the ign system

The point of looking at the ignition isn't to correct the obviously lean mixture it's to correct the dieing when he attempts to bring the car down to idle...  Actually a common issue with the M/P distributors when you run a cam that likes to idle above 800ish rpm's...

Might add if the springs that raise the needles were an issue it would be fat at idle, not lean...

[Topcat]

it may come down to drilling holes in the throttle plates so you can get the throttle plates closed down so the idle transfer slots are covered properly & idle mix becomes responsive again . Not sure you want to do this to rare factory carbs though . you might want to run it with cheaper carbs that cannot be seen under the shaker hood anyway . Have you swapped springs under the metering rods to make sure they are staying down at idle also

I really don't want to drill out the throttle plates.

Earlier AFB's are smaller top diameters than the new Carter replacements.
I could do that, but then I would have to also buy another air cleaner baseplate from shakerhood.com

They are expensive. Like $750 bucks.

[Chryco Psycho]

 I used to throw out the eddy carbs , no use for them , if you could get a couple just to try them at least it would prove the theory , maybe the tops would swap

[Topcat]

I used to throw out the eddy carbs , no use for them , if you could get a couple just to try them at least it would prove the theory , maybe the tops would swap

We swapped the bottom half of a later Carter putting top half of my OEM's with idle adjustments on the front carb a few months ago. Before I replaced the intake gaskets just last week.

No noticable difference in idle quality then.

[1 Wild R/T]

You can get a little extra air in to the engine without drilling the throttle plates by cracking the secondaries open slightly so you can close the primaries & possibly gain some idle mixture adjustability by exposing the transfer slots...

Without looking at your carbs I'm not gonna suggest how to crack the secondaries but since initially it's just a test I'm sure you could get creative..

[cudabob496]

the new Holley HPs have an adjustbable idle air
bypass screw, located right in the middle of the
ventries, that eliminates need for holes in throttle
plates.

[1 Wild R/T]

the new Holley HPs have an adjustbable idle air
bypass screw, located right in the middle of the
ventries, that eliminates need for holes in throttle
plates.

Yeah Barry Grant has it too & has for years... That doesn't help a man who wants to keep his Hemi looking stock with two Carter AFB's....

[cudabob496]

Yeah Barry Grant has it too & has for years... That doesn't help a man who wants to keep his Hemi looking stock with two Carter AFB's....

no one will see the holes in the trottle plates

[Topcat]

no one will see the holes in the trottle plates

these carbs are worth anywhere from $3,000 to $4,000 on the market.
I've seen them sell for this.

I'm not drilling these.

[1 Wild R/T]

Mike, where's you sense of adventure?    Like I mentioned earlier you might try opening the secondaries slightly... Assuming the primaries are opened far enough that the transfer slots aren't able to do their job...

[Topcat]

Mike, where's you sense of adventure?    Like I mentioned earlier you might try opening the secondaries slightly... Assuming the primaries are opened far enough that the transfer slots aren't able to do their job...

Sounds like a plan after the car show next week-end.

[cudabob496]

could always keep the original throttle plates, and temporarily install
new ones with holes to solve the issue.

Interesting that the throttle body throttle plate, on my LS1 Trans Am, has a small hole as well.

http://www.bing.com/images/search?q=ls1+throttle+body&go=Submit&qs=n&form=QBIR&pq=ls1+throttle+body&sc=8-17&sp=-1&sk=#view=detail&id=5189C45CE1444E12A225A50AE2FF8438DD2842D2&selectedIndex=3

[Topcat]

Have you swapped springs under the metering rods to make sure they are staying down at idle also

Which one's do you recommend?

[Chryco Psycho]

what vacuum are you getting at idle in gear , the springs need too be lighter rated than the reading you get so if you have say 6" of vacuum you need 4" springs