By 1965 Chevrolet had already solved the question of how to make a Corvette go fast. The harder problem was stopping it, and the four-wheel disc brakes that arrived that year were so far beyond the drums they replaced that Chevrolet offered buyers a cash credit to refuse them. Almost nobody took it. Then, in March, a 396 big block appeared on the order sheet and changed the conversation entirely. Here is what made 1965 the pivotal Sting Ray year.