For 1958 Buick went for heavy emphasis on its already massive fins. The 300 bhp Limited models were the most luxurious and longer than ever, but sales flagged. While using the same body shell as the 1957 Buicks, the 1958 Buick was very definitely different on the outside. Two longtime Buick identifiers were absent this season.
Both the vertical bar grille and the Ventiport were gone, but a stylish version of both would be back for 1960. The new 1958 grille was made up of what appeared to be about 150 free-floating chrome squares, evenly spaced, four rows in height for the full width of the car with round parking lights mounted at each end. The look was obviously bright and sparkly, but alas, the glitter did not end there.
Another Buick identifier, in its last appearance of the fifties, was a modified Sweepspear which began on the inside front edge of the headlight eyebrow, wrapped over and around onto the front fender side, then followed the traditional path to the front of the rear wheel opening, then continued to the rear wheel opening and straight back to the rear bumper. But on the rear quarter panel, all models wore some type of ornamentation that covered an area roughly 5 feet long by 1 foot tall, virtually the entire rear fender. Many considered this the pinnacle of chrome excess on American cars.
Powerplant choices remained the same, although the Fireball name was gone, replaced by the "B-12000," fitting in with the theme of "B-58 Buick." The "B-12000" name was taken from the fact that it developed a thrust of 12,000 pounds behind every piston's power stroke. Putting the power to the road was a newly engineered "Flight Pitch Dynaflow" with a truly infinitely variable stator. This new capability made the Flight Pitch Dynaflow one of the most responsive and smoothest transmissions ever produced. It was standard on the Limited and Roadmaster, and optional for the Super and Century.
Interiors continued similar to 1957, with some upgrades on higher series cars. Model changes were minimal, with the three-piece rear window Roadmasters being gone due to lack of public acceptance, and the Super Convertible being discontinued. A new ultra-luxurious Limited line replaced the previous Roadmaster 75, adding a convertible to the line, along with eight inches of length at the rear of the car.
The Limited nameplate had previously been used on top-of-the-line, limousine-like Buicks prior to World War II. Finally, the Special Riviera 4-Door Hardtop Estate Wagon and Century Caballero 4-Door Hardtop Estate Wagon both returned for a second and final season, as General Motors ended the four-year run of hardtop wagon models that included the Chevrolet Nomad, Pontiac Safari, and Oldsmobile Fiesta Wagons.