1965 Chevrolet Corvette L78 396 V8 – a Very Unique Corvette

The big-block V8 powered Corvette was a legend, however it only lasted for a brief 10 model years from 1965-1974. Even though the 396 cubic-inch big-block V8 Corvette was the first big-block V8 Corvette, for many years it was relegated to forgotten status. This was mostly due to the 396 Corvette only lasting just one half of a model year and then being overshadowed by the 427 and 454 cubic-inch big-block V8 Corvettes that followed it.

From 1957 until the middle of the 1965 model year Chevrolet’s fuel injected small-block V8 was the Corvette’s top performance engine. Chevrolet would have probably been content with continuing to offer its fuel injected small-block V8 as the Corvette’s top performance engine for many more years had it not been for the debut of the two seat Shelby Cobra 427 which was equipped with Ford’s 427 cubic-inch big-block V8. Chevrolet started off the 1965 model year with the powerful 375 gross horsepower (L84) fuel injected 327 cubic-inch small-block V8 as highest horsepower Corvette engine option. By the middle of the 1965 model year this engine was replaced by Chevrolet’s new 396 cubic-inch big-block V8 which was based on Chevrolet’s new Mark IV big-block V8 engine architecture. Chevrolet’s Mark IV based 427 cubic-inch big-block V8 wouldn’t be ready for production until the 1966 model year.

The Shelby Cobra 427 wasn’t solely responsible for the change in direction at Chevrolet concerning future Corvette performance engines. By 1965 Chevrolet had already reached the higher levels of the 327 V8’s potential. Most muscle car V8 engines during the golden era generated less than 1 gross horsepower per cubic inch of engine displacement however the 1965 L84 fuel-injected 327 produced an amazing just over 1.1 gross horsepower per cubic inch. The 1965 model year had 5 different output levels of the 327 small-block V8, the lowest was 250 gross-horsepower and the highest was 375 gross horsepower. The truth was that the Chevrolet’s 327 V8 needed a substantial growth in cubic inches to obtain more horsepower. Chevrolet’s Mark IV big-block V8 was the easiest and least expensive way to offer more power to Corvette buyers.

The Corvette’s L78 396 had a Holley 4-barrel carburetor and produced 425 gross-horsepower and 415 lb-ft of torque. This was a 50 horsepower and a 65 lb-ft of torque increase over the L84 fuel-injected 327. Compared to the L84 fuel injected 327, the L78 396’s abundant torque was available much lower in the rpm range where performance car buyers preferred.

Standard with L78 396 was the M20 4-speed manual transmission, optional was the heavy-duty M22 4-speed manual transmission. At the time the 1965 L78 396 Corvette was
lightning quick with a quarter mile time of just 14.1 seconds at 103 mph. The L84 fuel injected 327 Corvette in comparison ran the quarter mile in 14.4 seconds at 99 mph.

The really good news for Corvette buyers was the L78 396 option was only $292.70 versus the L84 fuel-injected 327 option which had a much higher price of $538. The L78 396 was also easier to work on and modify compared to much more complex L84 fuel-injected 327. A performance oriented 3.70 rear axle ratio was standard with the L78.

Visually the L78 Corvette looked identical to any other 1965 Corvette, with two exceptions. There were 396 badges on the front quarter panels and a large bulge located in the center of the L78 Corvette’s hood which was necessary so the hood could be closed. The Corvette’s standard hood didn’t offer enough clearance for the L78’s air cleaner which was higher due to the big-block L78 396 V8 being taller than the small-block 327 V8.

The 1965 model year also saw the introduction of the side exhaust system option (RPO code N14). It was a bargain at only $134 however only 759 1965 Corvettes were equipped with the option. The side exhaust system gave the Corvette a race car sound which could be heard a few city blocks away. Its deep resonance exhaust note was like beautiful music to any V8 engine enthusiast. Unlike the Shelby Cobra 427 which also had side pipes, Chevrolet used metal shielding around the exhaust system to keep the driver and passenger safe from the hot exhaust pipes when entering and exiting the car.

Though only 2,157 L78 396 V8 equipped Corvettes were produced for 1965 which was about 9 percent of total 1965 Corvette production, it was more popular than the 1965 Corvette with the L84 fuel-injected 327 V8 which had an extremely low production total of only 771 units. Starting in 1966, the 396 was replaced by Chevrolet’s larger displacement 427 cubic-inch big-block V8. By 1967 almost half of all Corvettes produced that year would be powered by a 427 big-block V8.

Due to it’s extremely short production life and it being a placeholder between L84 fuel injected 1965 Corvette and the L36 and L72 427 big-block V8 powered 1966 Corvettes, for many years the L78 396 Corvette was treated as a freak Corvette or an interesting anomaly in the Corvette’s long production life. Finally the L78 Corvette is the getting the proper respect it deserves and the currently fairly high prices on the collector market reflect this. Today the L78 396 Corvette easily makes the list of the top 10 most legendary Corvettes.


Click on the link below, to watch the video of this article via Old Car Memories’ YouTube channel:



Written contents in this article – © 2020-2021 Pete Dunton – All Rights Reserved