The third generation, or Series III of the Excalibur debuted for 1975. The Series III, which is also referred to as the SIII, was built as a two seat Roadster or four seat Phaeton. These convertible cars were offered as standard with a Corvette-sourced 454ci V8 engine that was paired to manual or automatic transmission options. Production of the Series III Excalibur ended in 1979, with the Series IV Excalibur replacing it.