1969 Dodge Dart Engine Stutter

Drove around the block and now it idles at 15.36 and sounds great!
Hmm. I turned the car off and came back 15 minutes later. Turned the car on and then turned on the head lights. Started making knocking noises. They went away after 4 minutes running. Those noises were what it was doing before, when it would start to sputter and die.