1966 vs. 1967
The Styling difference is fairly similar between a 1966 GTO and a 1967 GTO. The front grille difference is the 1966 GTO grille is mostly dark and the parking lamp housings are part of the grille. The 1967 grille has a bright, diamond-pattern mesh and the parking lamps are separate housings.
The rear difference is pretty easy to distinguish. The 1966 GTO has two sets of three taillamps and the script "PONTIAC" centered on teh tail panel where the 1967 GTO two sets of four taillamps and no script.
