i am looking at a mustang that i believe the engine has been replaced with ford engine that has a warranty but there are no receipts. i'm trying to find the engine number so i can call up ford and get some information about it. where should i be looking?

 

I know on the pushrod engines the numbers are above the starter on the side of the engine block. I'm interested in a definitive answer to this as well so i can determine what engine was swapped into my car as well.