1976 models featured steel floor panels shielding the catalytic converter exhaust. These steel floor panels weighed less than the previous fiberglass floor and reduced interior noise levels. Horsepower rose to for the base L-48 engine; for the optional L-82. To further reduce cabin noise levels, cowl induction was dropped in favor of the air cleaner ducted over the radiator, picking up outside air from the front of the car, thus reducing wind turbulence at the base of the windshield. The hood was carried over, with its cowl vent grille and induction system opening becoming non-functional. The optional cast aluminum wheels were finally made available, which reduced the unsprung weight of the car by 32 pounds. Nearly 15% of the cars were ordered with the new wheels at a cost of $299. A standard steel rim spare was used. This was the last year for optional white striped tires, as 86% of the cars were being delivered with the optional white lettered tires. A new rear nameplate for the rear bumper cover was introduced, eliminating the individual "Corvette" letters used since 1968. An unwelcome change was the "Vega GT" 4-spoke steering wheel, although its smaller diameter did provide extra room and eased entry/exit. The steering wheel, color-keyed to the interior, continued on 1977 through 1979 models, limited to non-tilt wheel cars only. GM's "Freedom" battery, a new sealed and maintenance-free unit, was now installed in all cars. The rear window defroster option was changed from the forced-air type of previous years to the new "Electro-Clear" defogger, an in-glass heated element type. Even without a convertible model, the Corvette still set new sales records.