Pontiac Sunbird Formula
The Sunbird was a typical hatchback-type GM compact of the ’70s and almost identical to the Buick Skylark or Chevrolet Monza. However, in the Pontiac version, the Sunbird had an interesting muscle version called the Formula and an optional V8 under the hood (via Autopolis).
The name Formula was from the Firebird lineup, and it always marked a model equipped with a V8 engine. If you chose the Formula, you could get a 305 V8 engine with 165 hp and a hint of performance. Since the Sunbird was relatively light, this Pontiac could be called a muscle car. But just barely.