help ID carb

Rob ,the 273 motors come with a 500 cfm carter afb carb.The number is located at the bottom left bolt hole,and there will be a four digit number and a letter or two letters,either S or SA.The numbers will start with 38,41,42,43.example:3853S,4120S and so on.I have a few of these carbs and may want yours for spare parts,mrmopartech