Being a huge fan of the movie, I've always seen this as a bit of a contentious issue. The Fury was only ever released in a shade of beige, and had a gold grille, plus gold on the side "spearline". Although Christine's engine is almost definitely from a Fury, I've always considered her body a Belvedere, since she has no gold on her at all. The only real difference between a Belvedere and a Fury was the engine and the gold trim, plus the Belvedere's options for different colours.