51 Chevy 216 carb tuning

I searched but could not find an answer. I was wondering how many turns out the mixture screw should be set at on a stock 216 carb. If anyone has an answer I would really appreciate it.

 

if i remember my day of carb tuning if it was way off i turned it closed came out 2 full turns and then went forward or back unitl i got it to idle real smooth. a bit tougher today with alcahol in the gas, it takes awhile for each adjustment to make its presence but that s th efun of old cars

 

hook up a vac gauge to manifold vac and adjust screw untill you get the highest vac signal.