How do I tell if my 73 camaro is a Z28?

My dad and I were given a free 73 camaro but I have no idea how to tell if its a Z28 or what was the other package LT?
 
It doesnt have an engine or tranny so where can I get a engine equal to what the 69-70 camaro had in it.

What is the VIN?  That could narrow it down a bit.

Here is a link that will help you decipher your tag.  It should be on the drivers side firewall...Under the hood....obviously...  Oh and take a rag cause it'll probally be just as dirty as the engine. haha.  This tag can also give you the original color of the car and interior colors etc....
 
http://www.nastyz28.com/camaro/camaro73.php