For 1975 although the basic body styling was unaltered, the Colonnade designation was dropped. The lineup was marked by fresh front and rear styling including a vertical grid-patterned grille and new bright trim around the headlights were highlights. Rectangular taillights sat flush with the body surface, connected by a brushed chrome panel. Malibu Classic coupes had distinctive opera windows. Landau coupes came with a vinyl roof, full wheel covers, whitewall tires, color-keyed body striping, and dual sport mirrors. Engines ranged from the standard 250-cubic-inch six and 350-cubic-inch 2-barrel V8 to V8 options of 400 and 454-cubic-inch size, the last with a 235-horsepower rating. Variable-ratio power steering was now standard with V8 models, and all 1975 models rode steel-belted radial tires. A new "Chevrolet Efficiency System" introduced a High-Energy Ignition (HEI). This electronic ignition system provided minimal maintenance and increased power. Speedometers were now calibrated in both miles per hour and kilometers per hour. Following its debut as a 1974 model, the sporty Laguna Type S-3 left the lineup briefly, then reappeared in January 1975. This time, it wore a rakishly slanted, urethane-covered aero-style nose designed for NASCAR (first use on a Chevrolet vehicle - later to show up on the 1983-88 Monte Carlo SS), louvered opera windows, and could be ordered with a vinyl half-roof. The 454 engine option was available for the first half of the model year after which the 400 engine became the top engine. Options included an Econominder gauge package, affirming again that the age of muscle was long gone.
Source: Wikipedia, 2012