Additional new features were an acoustical double-panel roof, tighter-fitting glass, flush style outside door handles, molded full foam front and rear seat construction, flow-through power ventilation system, inside hood release, refined Delcotron generator and sealed side-terminal battery, a larger 22 gallon fuel tank, and "flush and dry" rocker panels introduced first on the redesigned 1971 full-size GM cars. Another structural improvement was a stronger design for the side door guard beams. Options included swiveling Strato-bucket seats (with console) for coupes, a power moonroof, and Turbine I urethane (backed by steel) wheels, as was the instrument gauge cluster.