2. 1968 Pontiac Firebird 400
When Pontiac first introduced the Firebird, it caused quite a stir among performance-loving car buyers in America. It was a pretty coupe with a wide arrange of optional extras and one of the biggest engines you could get in a pony car: Pontiac’s 400 CID V8. Back in the late 60’s, GM had a rule that forbade car manufacturers to produce cars with more than one horsepower (HP) for every 10 pounds of the car’s weight.
The aim of this rule was to stop manufacturers from producing insanely overpowered models, so all GM’s products and brands had to follow this. The only exception was the Corvette. In 1968, Pontiac introduced the new Firebird with a 400 V8 engine which delivered 320 HP. Immediately after the introduction, car fans were publicly asking the factory why the new 400 V8 engine in the Firebird had 320 HP, while the same 400 V8 engine in the GTO made 366 HP.
Pontiac didn’t reply, but soon the answer came from insiders at the factory. The new Firebird 400 weighed 3,300 pounds. So, to make it eligible under the GM one HP per 10-pound rule, Pontiac had to rate the 400 V8 engine at 320 HP. Despite the underrating, the new Firebird 400 was fast, especially with the optional Ram Air induction system.