Story
1966 Buick Skylark Gran Sport 401
For 1966, Buick gave the Skylark Gran Sport its own Series 46 model identity and new Riviera-influenced sheet metal. The standard four-barrel 401-cubic-inch Nailhead was still advertised as a 400 and rated at 325 gross horsepower and 445 lb-ft of torque.
A three-speed manual remained standard. Buyers could choose a four-speed manual or the two-speed Super Turbine automatic, and the AMA specification records transmission-specific axle ratios plus optional Positive Traction. Late in the model year, the L76 engine option paired a Rochester Quadrajet with the Wildcat high-lift cam for 340 gross hp at 4,600 rpm and 445 lb-ft at 3,200 rpm; the reviewed reference limits it to automatic-transmission cars.
Buick built 13,816 Series 46 Gran Sports: 1,835 pillared coupes, 9,934 hardtops, and 2,047 convertibles. Those totals describe model production, while an individual car still requires its own VIN, body tag, drivetrain codes, dates, and paperwork.
Authentication starts with Series 46 and body codes 07, 17, or 67 in the VIN, then moves to the Fisher body plate and the engine production stamp. MR identifies the standard 325-hp 401; the exact production-code and date evidence for a claimed L76 must be verified on the individual car. Badges, hood scoops, wheels, or a swapped Nailhead do not prove an original Gran Sport.