Among GM's performance cars of the 1960s, SD has long been associated with Super Duty Pontiacs, such as the Super Duty 421 of racing fame. The 396 cid engine introduced in the 1965 Chevelle was a Chevrolet engine, the first of the MK IV big blocks that were derived from the MK IIs 427 cid 'Mystery Engine' first seen at the Daytona 500 of 1963.

The Beaumont was not a US market nameplate; it was introduced as a 1964-1965 variation of the Chevelle to become a unique GM muscle car with its own nameplate. Using the Chevelle body and Pontiac instrument panels among other elements of the GM lines, the Beaumont line was sold through Canadian Pontiac and Buick dealerships.

The SD was introduced as the top model, the Super Deluxe - not Super Duty - and incorporated Chevrolet's 350 horsepower 396 engine and Muncie 4-speed transmission to make a very rare car. For 1968, only 702 Beaumonth SD hardtops were built along with 65 convertibles that were the last of the Beaumont ragtops; none in 1969.