help needed with new carburetor

I have a 1970 dart 318 I'm working on and I need a new carb or a carb rebuild kit. The problem I'm having is my car is originally a 318 however I have no idea if it's the original one or anything. I have a carter 2bbl but the tag is missing on it to identify what it is. How do I go about choosing a new carburetor or rebuild kit? Thanks!