1968 Dart 273 intermittetent engine issue
That thing got Solid lifters?
cuz you know, if they are getting tight, increased coolant temp/normal increasing coolant temps, might be driving a few exhaust valves into insufficient seat time to cool off, and away goes your cylinder pressure.
Or if the intakes don't seal, and they leak pressure back into the intake, same thing, loss of pressure; but now, you also loss of engine vacuum, so she may idle like it has a "bit of a cam" in her .
Still runs great cold, cuz none of thatchit is going on. yet.
Jus saying.