Chevy uses a letter to designate each model. The Corvette is the Y-body, the Camaro/Firebird is the F-body, and I think the Montie Carlo is the A-body. Those are the only ones I can remember off the top of my head though.
Chevy has a strange proibition against using engine codes on the outside of 'Vettes. Originally the ZR-1 was going to be called the LT-5 after the engine, but that was shot down and the ZR-1 designation was resurected.
I may be wrong in this, but if you have noticed, all of Chevy's top end performance packages all have the "Z" designation, Z06, ZR-1, Z71, Z-28, Z-34.... I have heard that this is in honor of Zora Duntov.