Buy this 273?

I'm not totally sure, but. Trans looks like a 727. If that is the case, and the engine is a 1967, you might have an issue using that trans with that engine. Slant six and small blocks had a smaller diameter crank pocket untill 1968, when the pocket was made larger. All 727 trans had converters that fit the large crank pocket, and will not fit the early/small engine.