9. Chevrolet Impala 454
Impalas had a long relationship with performance. In fact, some of the best full-size muscle cars were Impalas with 409 and 427 V8 engines and the SS package. However, all those models were two-doors, so although Chevy offered the 427 in a hardtop sedan, it didn’t have the same power ratings and performance. Fans who wanted big cars with big power had to wait until 1971 when Chevrolet debuted their fifth generation Impala.
It came with a big block 454 V8 engine and 345 HP on tap. The large, heavy car had some performance edge and proved that Impalas still had some muscle car spirit in them. Unfortunately, the following years marked a sharp decline in performance. So the once mighty 454 V8 produced only 190 HP for 1976, which was the final year for this engine option.