Quick/dumb question- how to visually identify a 340 vs 360 vs 318 (with a 4bbl)?

I just found an ad for what is supposedly a 360 4bbl for sale. The ad claims however that the motor came out of a 1971 Dodge Dart "collector car" that was crashed. Obviously, this could have been an engine swap or the seller could have the year wrong...but how can a guy tell?

It's easy to know what the motor "should be" based on model year. Likewise, it's easy to spot a Magnum motor... but when it comes to telling the LAs apart, especially when dress-up parts have been added, I can't say that I know the difference!

Any clues that I should look for?
Thanks!!
Mike