64 Dart 270 ignition struggles

Could be either, both, or other things. Have you / do you know how to perform a tuneup? What do you have for tools / instrumentation? If this is a breaker points (original) ignition, you really should get a dwell meter, unless you are planning on ditching the system for an electronic conversion, or are planning an engine swap

1...Check compression and or leakdown test and if never been done, check/ set valve lash
2....Examine condition of points, examine cap and rotor, test plug wires, and examine or replace plugs
3....Replace points if necessary, and condenser, and reset point gap AKA dwell
4....Set ignition timing
5...Warm engine completely and set idle speed and mixture

That is the short version. Check air filter condition, condition of fuel and vacuum hoses, carb bolts (they can loosen) and choke operation. Check for gummy/ rusty/ stuck carb linkage, choke pull off etc etc.

IF YOU do not have one, run over to MyMopar.com and download the closest year factory service manual. You may have to settle for Plymouth vs Dodge etc