Isn't Bart strong and smart!

How strong and smart Bart is!

Bart is amazingly strong and smart!

CJ

Boy, am I hungry.

What does the above EXCLAMATORY sentence mean?

TeoBoy, am I hungry!!!

What does the above EXCLAMATORY sentence mean?

I'm really hungry!

'boy' is a common exclamatory word which has mostly lost its meaning as a young male child when used in this context. However, a word of caution. I would not use the exclamatory 'boy' in a conversation with an African-American man, since it used to be used with derogatory intent, especially in the days of slavery in America. I made this mistake once quite innocently and received some dirt

Isn't Bart strong and smart!

Is Bart strong and smart!

Do the above exclamatory sentences have the same meaning?!

As an exclamation I would say yes, they are saying the same thing.

Wow, that sure was easy!
Wow, was that easy!
Wow, wasn't that easy!
http://www.eslcafe.com/forums/stude

Was that easy! and Am I hungry! are particularly American constructions. I don't think we have this inversion for an exclamation in BrE.
When we use the negative, it's formally an interrogative, so if I say Isn't he clever? it's like asking Don't you think he's clever? However,

Should we read these exclamatory sentences with falling intonation, rising intonation or either?

falling intonation
http://www.eslcafe.com/forums/student/viewtopic.php?p=84699#84699