What was the first year Corvette was offered with a Big Block engine?

The first big-block Corvette was offered in 1965 as an L78 396-cubic-inch V-8. It had a cast iron block and heads, an aluminum intake manifold, solid lifters, and big Holley carburetor. It came with an added cost of $292.70 and was installed in 2,157 Corvettes. With 425 hp it was the most powerful Corvette up to that time. The following year cubic inch displacement was increased to 427 for the 1966 model year.