The 1978 Mustang II King Cobra was the first Mustang model to use Ford’s 5.0-liter marketing designation. Its engine was the familiar 302-cubic-inch V8, but the “5.0” badge helped establish terminology that later became strongly associated with Mustang performance.
The King Cobra was a limited-edition, V8-only version of the final Mustang II model year. It featured a deep front air dam, bold striping, and a large cobra graphic inspired by the Pontiac Trans Am’s visual language. Ford produced 4,313 King Cobras for 1978.
Cobra II is an easy choice to confuse with the answer because it was another sporty Mustang II variant, but the King Cobra came later and carried the first 5.0 badge. Ghia was the luxury-oriented trim, while Mach 1 was a separate performance nameplate used during the Mustang II era. The 5.0 designation later became iconic on Fox-body Mustangs and subsequent generations.