Second generation (1965–1970)
In 1966 a one-year-only Wildcat "Gran Sport Performance Group" package could be ordered by selecting the "A8/Y48" option. Two engine choices were available. The single carb 425 CID/340 hp V8 was included in the base package price with a 360 hp dual-carb set-up available at extra cost. Initially, this 20 hp upgrade remained a dealer-installed carb-intake modification bolted to stock MT-coded engines but eventually these "Super Wildcats" could also be obtained direct from the factory with MZ-coded engines. Rounding out both the base and Super GS packages were dual exhaust, heavy-duty suspension, posi-traction and updated rear quarter-panel "GS" badging in the new, initials-only format employed on all post-1965 Gran Sports. A total of 1,244 Wildcat GSs were built by Buick during the model year. Of those, 242 were convertibles and the rest were hardtops. A mere 22 (consisting of an unknown mix of both body styles) were Super Wildcats.[3]
A styling appearance cue was adopted from the popular 1963 Buick Riviera, where the beltline arched up over the rear wheels, a modification of an older styling element called the "Sweepspear," with later vehicles installing a rub strip along the entire side of the vehicle tapering down as it reached the rear bumper.
The year 1967 brought a new engine to the Wildcat line (along with the Riviera and Electra 225) – a 430-cubic-inch V8 with four-barrel carburetor and 360 hp rating that featured larger valves for better breathing than the previous 401/425 Nailhead design that dated back to Buick's first V8, in 1953. It had a 10.25:1 compression ratio and a four-barrel carburettor, with maximum power reached at 5,000 rpm and 475 lb.ft of torque at 3,200 rpm - all SAE gross values. The 430 was relatively short-lived as it was only offered through the 1969 model year. For 1970, the 430 was superseded by the largest Buick V8 engine ever – a 455-cubic-inch engine that was basically a bored version of the previous engine with the same large-valve design, a horsepower rating of 370, and torque rating of more than 500 pounds.
1967 and 1968 saw the addition of new federally-mandated safety equipment that provided better occupant protection in collisions, and accident avoidance features as well. Like other full-size U.S. cars of the late 1960s, the Buicks became bigger, plusher, and less economical.[3]
The Wildcat was offered only in Custom trim for its final year of 1970. It was replaced by the Buick Centurion for 1971.