1967 Dodge Dart 273 question factory single exhaust/

Hello everyone I’m trying to decide if I put back single exhaust or dual for my 1967 273 . I’m restoring the car and I’m not sure if I will gain more performance
I know the looks is much better with dual exhaust. I call few companies for dual exhaust and it seems tight for 67 to do. Any trick or suggestion
Thank you

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