A 56 or 57 Corvette. The body design was identical. But there was a difference on the inside!
From Edmunds Corvette history:
Visually, the 1957 edition was virtually identical to the '56, but inside, a four-speed manual transmission (the great T-10) was available
for the first time. The standard Corvette engine grew to 283 cubic inches and 220 horsepower, breathing through a single four-barrel
carburetor. Best of all, for the first time, Chevrolet offered performance-upgraded engines as options. In addition to the base configuration,
the 283 could be had with dual-quad carbs rated at either 245 or 270 horsepower or, best of all, with Rochester mechanical fuel injection.