Carter/Ball carburetor- Help ID

1971 Dart
Running a Holley 1BL (6260-2) so this would be a 1920? It needs a rebuild due to leaking, and stumbles bad on acceleration.

Before I do that, I also have a Carter which was included with the car when I purchased it. There is no tag, so not even sure of the model. Is this identifiable? If so, do you have an opinion as to which carb I should use? Better gas mileage with the Carter?

Thanks,
M
Sorry, forgot the pics. Here they are.

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