Known as one of the most beautiful American cars of its era, the first-gen Riviera received an infusion of muscle in 1965 thanks to the addition of the Gran Sport performance package.

By the late 1950s, GM was racing to come up with an answer for Ford’s highly successful second-generation Thunderbird, which spawned a new market segment dubbed “personal luxury car.”

In 1961, the corporation’s styling department, led by the great Bill Mitchell, developed a breathtaking Rolls-Royce-inspired concept codenamed XP-715, unveiled as the Cadillac LaSalle.

However, despite the overwhelmingly positive public reaction to the sharp-edged two-door hardtop, Cadillac’s decision-makers opted against series production.

Nevertheless, GM still wanted to produce the LaSalle, so all other divisions began an internal competition to takeover the project.

Buick, desperate for a new, exciting model to revive public interest in the brand, made the most convincing pitch and, with Bill Mitchell’s blessing, was given the reins to GM’s new personal luxury car project.

With few alterations to the initial design, the XP-715 LaSalle concept officially became the series production Buick Riviera in October 1962 as a 1963 model.

The final, most exquisite version of the first-gen Riviera

Photo: Mecum

 

During the first two model years, the Riviera succeeded in reviving the Buick division. Moreover, while it didn’t outsell the T-Bird, it successfully filled the personal luxury gap in GM’s lineup.

Universally praised for its stunning design, the model received one final set of styling improvements in 1965, becoming more elegant than ever.

While most of the styling upgrades were visible from the door rearwards, the most iconic 1965 feature was the electrically-actuated, two-piece headlamp covers.

When closed, the covers bolstered the aggressive look of the Riviera and complemented the redesigned egg-crate grille perfectly.

The debut of the Gran Sport package

Photo: Mecum

 

The 1965 model year it also marked the debut of the Gran Sport performance package, Buick’s answer to Pontiac’s GTO.

While the Gran Sport debuted on the Skylark A-body intermediate, aiming to compete directly with the GTO, Buick also made the package available on the Riviera.

Like its intermediate sibling, the Riviera Gran Sport came with a special version of the venerable “nailhead” V8, but in the case of the personal luxury car, the engineers went for the largest-displacement version instead of the 401 (marketed as a 400 in the Skylark GS).

The Riviera Gran Sport’s standard V8, a 425-ci (7.0-liter), was dubbed Super Wildcat. It was based on the “stock” 425 (optional on the non-GS 1965 Riviera), which received several minor upgrades in 1965, such as sturdier webbing around the mains and better-sealing piston rings.

But, while the standard 340-hp 425 (called Wildcat 465, after its peak torque output) came with a single four-barrel carburetor, the Super Wildcat was equipped with a twin four-barrel 600-cfm Carter AFB setup, a corresponding intake manifold, and a slightly larger-diameter dual exhaust system.

With these upgrades, the Super Wildcat was rated at 360 hp and 465 lb-ft (630 Nm) of twist. That wasn’t a huge improvement over the optional single-carb 425, but compared to the standard 1965 Riviera, which came with a 325-hp 401, the Gran Sport was unquestionably more muscular.

A reasonably quick land yacht praised for its maneuverability.

Photo: Mecum

 

Linked to the three-speed Super Turbine 400 transmission, which many dubbed the most advanced automatic of the day, and a limited-slip differential that came standard with the GS package, the Super Wildcat helped propel the nearly two-ton machine from 0 to 60 mph (97 kph) in just under 7.5 seconds.

Add to that a 15.3-second quarter-mile sprint in bone-stock form, and there was no question that the Riviera Gran Sport was a land yacht that packed some adequate muscle.

In addition, the 1965 Riviera, like all other Buicks of the era, was praised for its maneuverability. Though the independent/live axle suspension setup was nothing new or innovative, its geometry was dialed in, resulting in a smooth ride and surprisingly crisp handling for such a large vehicle.

Furthermore, the car featured huge 12-inch finned aluminum, power-assisted drum brakes front and back, which were some of the most effective and durable on the market.

In contrast to the Skylark’s Gran Sport, the Riviera performance package did not include suspension upgrades. However, buyers could get an optional ride and handling package that brought heavy-duty shocks and springs that lowered the ride height by one inch, as well as a quicker 15:1 ratio steering gear.

The 1965 Buick Riviera Gran Sport today

Photo: Mecum

 

During the 1965 model year, the last for the first-gen Riviera, Buick sold 34,586 units of the personal luxury car.

The mix between popular luxury and muscle car-inspired performance wasn’t that appealing for buyers since only about ten percent (3,354) checked the Gran Sport package on the order sheet.

However, nearly six decades later, the first-ever GS Riviera, with its timeless design, one-year-only hidden headlamps, and healthy dose of V8 muscle, is an icon from the golden age of American design.

According to classic.com, the average value for a surviving example currently stands at $89,108, nearly four times the average value of the 1965 Skylark Gran Sport.

Of course, there are pristine examples with rare options that demand even more, such as the special order Champagne Mist example above, which sold at a Mecum auction earlier this year for $302,500.

In the YouTube video below by CENTER LANE, you can watch the fascinating story of a surviving example of this iconic American ride.