I kinda look at it this way; All the old stuff from the mid 60's until 1977 I call an "A" body due to the larger frame platform. While I understand some 78 and 79's may be considered "A" body's too according to GM, I call them "G" body's due to the smaller frame and platform they're built on. I think most guys here would agree even though we know the they are technically not according to GM. Just like a 1999 Riviera "MAY" be called a "G" body, everyone knows it's really not. That is why GBody is recognized from 1978-1988.