1968 Pontiac Firebird 400
When Pontiac unveiled the Firebird, it caused quite a stir among the American performance-loving car buyers. It was a coupe with a wide arrange of optional extras. Also, it had one of the biggest engines in a pony car, the Pontiac 400 CID V8. Back in the late ‘60s, GM had a rule forbidding the car manufacturers from producing cars with more than one HP for every 10 pounds of weight.
The aim of this rule was to stop them from producing insanely overpowered models. And all GM products and brands had to follow this. But the only exception was the Corvette. So, in 1968, Pontiac introduced the new Firebird with a 400 V8 engine with ratings of 320 HP. Immediately after the introduction, car fans were asking why the new 400 V8 engine in the Firebird delivered 320 HP while the same engine in the GTO produced 366 HP.
However, Pontiac didn’t reply and soon the answer came from factory insiders. 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.