setting the step down idle on 1963 cadillac

I am selling my 1963 Cadillac and when it is all warmed up, it runs pretty well but when its cold and i fire it up, then shift into gear, the step down idle stalls the car out. This freaks out buyers obviously. I don't know a lot about setting the idle better, is there an easy fix?

here is the Carter Carb I am running.

 

No tips?

 

That appears to be the original Carter. Carter's are cold by nature. I would just keep a can of carb cleaner around or starting fluid and just shoot some of that down the carb before starting it. Also, I've found that warming up the car before someone shows up makes it easier to start too.