February 17th, 2021 Chris Phillip

Even though the 1965 Corvette didn't look a lot different than the previous year's edition, there was a lot new under that sexy fiberglass skin. Sure, there was a new hood, functional fender vents, new side-exit exhaust system and some trim differences but it was the 1965 model year that saw the first significant mechanical upgrades of the C2 platform.

First off, the 1965 Corvette could now be had with four-wheel disc brakes, which was a monumental upgrade from the previous drum brake system. With four-piston calipers, as well as 11.75-inch rotors front and rear, their addition represented a true turning point in overall vehicle performance.

And as great as that was, it wasn't even the most significant upgrade to the Corvette. The new Mark IV 396 V-8 made its only appearance in the Corvette that year and it was the first time a big-block V-8 was ever factory-installed in a Corvette and the first time an engine over 400 horsepower was available.

The Corvette version of the 396, known as the L78, had all of the best parts available that year, with four-bolt mains, rectangular port heads with 2.19-inch intake and 1.72-inch exhaust valves, 11.0:1 compression, forged steel crankshaft, a solid lifter cam, an aluminum intake manifold and a 4150-series Holley four-barrel. It was rated at 425 horsepower at 6,400 rpm, with 415 foot-pounds of torque at 4,000.

This engine was a substantial upgrade in forward motion, without a significant penalty in handling, as the chassis was designed with larger engines in mind. Even with the 650+ pound engine up front, the front-to-rear weight balance was still at a near-perfect 51/49 percent.

The performance was impressive by even today's standards, with 0-60 times of 6.0 second and a quarter-mile ET of 14.1 seconds at 104 mph. Obviously, stickier tires would have helped tremendously.

As it turned out, the 396 was installed in just 2,157 Corvettes for 1965. It would be replaced with a larger 427 for 1966, as displacement rules relaxed for smaller than full-sized cars that year. It was essentially the same engine as the L78 with a larger 4.25-inch bore. Interestingly, the horsepower rating for the larger engine still topped out at 425 horsepower. Was there some understating of power levels of one or both engines? That has been a topic of debate for half a century!

Story By Don Keefe

Photography courtesy of Dream Giveaway Garage