1964 Dodge Dart manual

If there’s no mention of the 273, most likely it was printed before the mid year release of the 273. The reference to a 318 is referring to the Poly 318 available in B Bodies and possibly other models as well. Usually the FSM cover more than 1 car line. For example my 65 FSM covers the Dart and Coronet. My 69 manual covers A and B Bodies.