Okay, here's my take:
318:
Comes with the transmission (that's a 3 speed 904 Torqueflite, by the way), torque convertor, and all linkages.
Correct oil pan.
Direct bolt up to 273 engine mounts and brackets.
You will still need a '70 and up radiator, a '66 Dart driveshaft (6 or 8, both used a 904...