 With the introduction of this V8, the six-cylinder engines were discontinued; a six-cylinder would not return to the full-sized Pontiac line until the GM corporate downsizing of 1977.A four-cylinder engine was introduced in the Tempest model line in 1961, followed by an overhead-cam six-cylinder starting in 1966, as well as on the Firebird.It was the first popular-priced, mass-produced engine in America using an overhead-camshaft configuration.