1964-’65 NY World’s Fair Animated Cut-Away 396 Big-Block Engine
The Mark IV big-block engine was intended to be a replacement engine for the W-Series 348/407/427 truck engine. But very quickly in the development phase it was discovered that the engine was a torque monster.
When released in spring of 1965 in the Corvette as the 396/425 L78 for only $292, it was obvious that it was easier to make big horsepower and torque with the new big-block to the more exotic and expensive ($538) L84 Fuelie. The rest is history.