The first subcompact car design developed by GM, the rear-wheel drive H platform initially underpinned the Chevrolet Vega and its Pontiac Astre counterpart.

For 1975, the H platform was expanded from entry-level vehicles to sport compacts, adding the Chevrolet Monza, Buick Skyhawk, Oldsmobile Starfire, and Pontiac Sunbird.

Following the 1980 shift of the X-body compacts to front-wheel drive, the H platform ended production for the 1980 model year.

From 1986 to 1999, the H platform designation was revived for front-wheel drive full-size sedans of the Buick, Oldsmobile, and Pontiac divisions.

In slightly over two years, GM sought to develop its first subcompact with a sub-2000 pound curb weight, an all-aluminum engine, and priced at or less than the Volkswagen Beetle; assembly of the vehicle was to be primarily automated.

In 1972, a prototype Vega powered by a 302 cubic-inch aluminum-block V8 (derived from CERV I) was tested, but did not progress to production.