15. Chevrolet Chevelle SS 454
The Chevrolet Chevelle was always a popular muscle car. After all, the combination of an affordable price, nice design and powerful engine was a hit with buyers. But for 1970, Chevrolet offered an expanded line of engines including the famous 454 V8 big block. They named the regular version of the LS5.
Although it was powerful, there was an even stronger LS6 variant they installed in just 3,700 cars. The LS-6 had an almost racing compression of 11.25:1. Also, it used a bigger carburetor and much stronger engine internals. Even though they rated it at 450 HP, it is more likely that it produced over 500.