This 1957 Chevrolet Bel Air wears a drivetrain Chevrolet never actually offered that year — a modern 350 crate engine swapped in place of the factory’s top-spec 283. Chevrolet’s real 1957 lineup topped out with a fuel-injected small block that made history as GM’s first one-horsepower-per-cubic-inch engine. Read on to find out what made the factory Tri-Five drivetrains so significant, and why so many owners choose a modern small block swap instead.