Carb and running issues need advice

[nathan.hall1]

I have a 351w with a 2150 Motorcraft on there I got it idling and accelerating pretty good in Park, I have the timing at 12 degrees, I put it in drive and the idle goes way down it hesitates and stalls. Put it in park it's good again? Is it a vacuum issue maybe?

 

[broncnaz]

Idle mixture and idle speed needs to be adjusted while in gear with a auto tranny.

 

[Gray035]

I was just having a similar problem. I think mine had a vacuum leak where the carb met the spacer. I doubled up the gaskets and that helped. I also stripped the carb down and blew out all the passages with air.

 

[pcf_mark]

Is your vacuum advance connected to the ported vacuum on the carb or to manifold vacuum?

Manifold vacuum would be the wrong set up if you have an A/T. Drop it into park the vacuum drops, advance goes away and the engine speed slows down and the idle goes to poop. Ported vacuum is the same at idle in neutral and gear.