Numbers Matching?

don't be too quick to knock that cast crank '73.There are not many around and someone that wants to keep his '73 correct would probably pay you well for one.Rebuilt you can treat it like an early block internally and the cast crank will be fine.
..as for the best blocks i have read the '70 blocks had the highest nickel content and are the most desirable but don't know if it's true.
$3000 for a used 340 is a crapshoot!