Slant 6 wont idle after warm

I'd start by swapping the ballast resistor. Cheap, easy and a common problem. Does it start, and then die when you left off the key? I think they usually fail open, but could be getting hot and changing resistance/opening up. Next would probably be the coil for similar reasons. I would think the points are OK at the moment, but I forget what happens if the condensor fails. Oops! Misread question, thought it died after getting warm and wouldn't start until cooled down. Advice still might apply though.