20. Chevrolet Corvette ZL1
Chevy presented the new, third generation of the Corvette in 1968. It brought a new, sleeker design they called the “Coke bottle” look. The mechanics, chassis, and drivetrain were the same and it was still great value for the money. The C3 generation included some of the most powerful Corvettes, but none was more powerful than the ultra-rare and legendary ZL1. The heart of the ZL1 was the racing-spec aluminum 427 V8 delivering with up to 550 HP in mild tune. This monster of an engine was far more powerful than anything Mopar or Ford had in production at the moment. Chevrolet produced around 200 of those engines. While most of them went to Can-Am racing teams, Chevrolet made around 12 test Corvettes with that engine in late 1968.
The performance potential was unbelievable, so Chevrolet didn’t want to offer this wild racing engine to the public. So they never mentioned the ZL-1 option to the press or in their official brochures. However, wealthy individuals close to the factory knew about its existence and could purchase the ZL-1. And that is why only two Corvette ZL-1s are known to exist, a yellow and a white one. One of them is manual and the other is automatic. Chevrolet destroyed the rest as pre-production prototypes, so only two found a way to private hands. Those owners have cherished and preserved them as the most valuable and interesting pieces of Corvette history. The cost of the ZL-1 option was over $4,000 on the base price of a big block Corvette C3, but today, the estimated value is over $1 million.