PCV issues?/hesitation

1965 Dart with a slant six is not OEM with a two barrel carb. So it is very possible there is a mismatch between the carb and the manifold. Also I'm not positive, but I don't think any slant six got a Rochester 2bbl carb. It is possible you could modify the base gasket so the carb will see vacuum. But I don't think that is your problem. Sounds like a bad accelerator pump shot.
If I'm not mistaken the 2 bbl carb on a big block has a larger bolt pattern then the 2 bbl carb for a small block or a slant six. So something doesn't seem right. can you post some pics of the carb and the manifold?