The Chrysler Hemi and Chevrolet big block did more than power quarter-mile passes. They became shorthand for two rival philosophies of American horsepower, each with its own mythology and fan base.

Chevrolet’s big-block V8s have never been subtle, and few pairings spark more debate than the 396 and the 454. Both are Mark IV “Rat Motor” legends, yet they deliver power, character, and practicality ...