Complex sentence: Earl's Buick Y-Job was the first concept car, he started "Project Opel", which eventually became the Chevrolet Corvette, and he authorized the introduction of the tail-fin to automotive styling.
Split into simpler sentences: Earl's Buick Y-Job was the first concept car. He started "Project Opel", which eventually became the Chevrolet Corvette, and he authorized the introduction of the tailfin to automotive styling.