The Firebird and Camaro were completely redesigned for the 1982 model year, with the windshield slope set at 62 degrees, (about three degrees steeper than anything GM had ever tried before), and for the first time, a large, glass-dominated hatchback that required no metal structure to support it. Two concealed pop-up headlights, a first on the F-Body cars, were the primary characteristic that distinguished the third generation Firebird from both its Camaro sibling and its prior form (a styling characteristic carried into the fourth generation's design). In addition to being about 500 pounds (230 kg) lighter than the previous design, the new design was the most aerodynamic product GM had ever released. Wind tunnels were used to form the new F-Body platform's shape, and Pontiac took full advantage of it. The aerodynamic developments extended to the finned aluminum wheels with smooth hubcaps and a functional rear spoiler.