The full-size 1955 through 1957 Chevrolet passenger-car line had been immensely successful, yet Chevrolet styling took a new direction in 1958. The 1958 Chevrolet Bel Air looked nothing like its 1957 predecessor, as all full-size 1958 Chevrolets received fresh and new bodyshell designs, which they shared with Pontiac. With the all-new X-member 'Safety Girder' frame design and four-wheel coil suspension  the 1958 Chevys were lower, wider, longer, and more luxurious, with the 283 CID V8 remaining as the mainstay powerplant. New for 1958 was the first of the company's big-block powerplants, with the 348 available in four different states of tune. The 348 CID 'Turbo thrust' was essentially the company's truck motor and Chevy's second-generation V-8. It was called the 'W' engine, referring to the shape of its valve covers, and would eventually evolve into the legendary '409.' With tri-power , the engine developed an impressive 280 horsepower.