Hemicuda idle issues

[antonellomopar]

Hello from Italy
I have some problems with the idle setting on my 70 Hemicuda. Car is all original, with OEM carbs and distributor and a Comp Cam 292 camshaft.Crbs have been rebuilt by Scott Harm Smith, but I am unable to get a good idle. I have set the idle mixture with two turns of the mixture screws from completely closed, on both carbs. The throttle screws are completely backed out on the rear carb, while slightly open on the front carb. The idle speed is controlled by the stock solenoid. Can't get the car to idle smoothly, sometimes tries to shut off...and idle is very erratic, with idle around 1200 rpm on the stock tach. Besides, the smell off the exhaust is bad, and eyes are watering. What am I doing wrong? Car is very responsive at higher speeds, pulls very strong to 6000 rpm, and doesnt ping on 95 octane gas. Only problems are at idle...
Thank you for the help

[Chryco Psycho]

I bet you have a lack of vacuum at idle probably under 8" due to the Comp cam which never work well in Mopars .
So now  you need smaller air bleeds in the carbs, but this is not possible in Factory carbs which were matched to the cam , the fix is to insert a small diameter piece of wire into the air bleeds for the idle circuit on both carbs, you may have to remove the top of the carb to do this , the wire will restrict airflow which will make the idle circuit respond better , you may need to try different diameter wire to get it to run best , make sur the wire is pinched somewhere close by so the engine doesn't inhale it !

[DeathProofCuda]

Do you have another option besides the factory tach for checking the idle speed?  If not, get one.  I use something like this.

https://www.ebay.com/itm/286533420369?chn=ps&mkevt=1&mkcid=28&google_free_listing_action=view_item&srsltid=AfmBOooDFEXY5wNPCmpfjMmXLc827N3S83BBjhRKZENBDZE1lszxjxXYJEk

Where is your timing at?

What happens when you turn the idle mixture screws in?

[RUNCHARGER]

I've run that camshaft in an otherwise stock Hemi and it worked just fine. I didn't even change the enrichener springs. Check for a vacuum leak or something incorrect in the carbs. It will run better (assuming no vacuum leaks) with 20 degrees initial timing with 34 total.
If you could supply us with what your initial timing is set at (and if is steady at idle) and measured vacuum  at idle it will help. Of course 1200 RPM with a mild camshaft like this is not really idling.

[antonellomopar]

Timing at idle is 18...at 2000 rpm is 38 degrees. I have discovered that the idle screw for the front carb was not turned correctly, gave it one and a half turn, and everything is much better. Thank you for the help

[RUNCHARGER]

Perfect: Thanks for the update.