29. Pontiac Firebird Trans AM 455
The 1971 Firebirds and Trans Ams were practically identical to those 1970 models. In fact, they still represented one of the best muscle cars in the rapidly changing market. But 1971 proved to be the last true muscle car model year that buyers could get high powered and legendary engines. In fact, just a year afterward, in 1972, horsepower ratings started to go down.
But the biggest news for the Firebird/Trans Am lineup was the introduction of the mighty 455 V8. It was the biggest engine ever to appear in this model. Since they lifted the GM displacement ban in 1970, all divisions rushed to introduce big-block engines in their muscle cars. Pontiac did just that in 1971 for their Formula and Trans Am models.
The 455 V8 produced 335 HP, but most muscle car enthusiasts will say they underrated that number. For instance, even with a higher compression in the Trans Am H.O., that 455 V8 had the same horsepower figure. So the real output was closer to 400 HP with a corresponding performance and top speed.