For a brief moment, the 425-horsepower Mark IV 396-cu.in. V-8 was top dog of available Corvette engines, producing higher output for less money than the fabled Rochester fuel-injected 327. To highlight the features of its new-for-1965 396, Chevrolet even created a cutaway display version for GM’s Futurama Pavillion at the 1964-’65 New York World’s Fair, but, by the time the engine made the stage, it was already obsolete. One of two built for the Futurama display, this recently restored 1965 Chevrolet Corvette cutaway 396 Turbo-Jet will cross the auction block in January, part of Barrett-Jackson’s 2019 Scottsdale, Arizona, sale.
In 1964, Corvette buyers had a choice of four engines, each with a displacement of 327-cu.in., ranging from the base 250-horsepower variant to the 375-horsepower “fuelie.” In between these extremes, buyers could opt for the L75 V-8, which produced 300 hp, or the L76 V-8, which made 365 hp. These choices carried over into the 1965 model year, and were joined by the 350-hp L79 and, in March 1965, by the 425-hp, 396-cu.in. L78. In slightly detuned form, the Mk IV 396 found its way into the Chevelle Z16 and fullsize Chevrolets, too.
The basic operation of a four-stroke engine can be broken down into four stages: intake, compression, power, and exhaust. Simple as that sounds, the inner workings of an internal-combustion engine remain a mystery to most people – including many passionate about cars – something that Chevrolet had learned from experience with earlier cutaway engines. In preparing its new 396 for display, workers cut away the cylinder heads, the intake and exhaust manifolds, and even the engine block itself. A transparent distributor cap was used and the valve covers were manufactured of clear plastic, allowing visitors to witness the offset rocker arms in action.
Driven by an electric motor, the engine showcased each stage of the combustion process, starting from the time the camshaft rotated to open the intake valve via a pushrod. Next came the compression stroke, where spectators could witness the crankshaft spin the piston to top dead center, followed by a “spark” (in the form of a red light bulb, briefly lit) that signaled the power stroke. Finally, viewers could see the camshaft open the exhaust valve (again, via pushrod) as the piston traveled upward on the exhaust stroke. For those unfamiliar with the process, it was magic.
The cutaway 396 didn’t stop there. The oil filter was sectioned, allowing viewers a peek inside, and the water neck was halved to show off the location and appearance of the thermostat. The transmission bellhousing had viewing windows, too, giving a glimpse at the flywheel and clutch assembly, though the M20 four-speed transmission itself was likely just a hollow shell.
Joining the 396 Turbo-Jet engine in Chevrolet’s Futurama exhibit was a cutaway Corvette Sting Ray, complete with a body that lifted off the frame to reveal the inner workings of the fuel-injected 327, its four-wheel independent suspension and its new-for-1965 four-wheel disc brakes. The Mako Shark II concept was displayed as well, giving attendees a hint at what the third-generation Corvette would look like. Ironically, the Mako Shark II was the only exhibit that spoke to the Corvette’s future.
The L78 396 essentially rendered the fuel-injected 327 obsolete. Consider the economics: The big-block V-8 carried an upcharge of $292.70, compared to the Rochester fuel injection’s $538.00. Even factoring in the items that were required for the 396 (including the $43.05 Positraction rear axle and the $75.35 transistor ignition system), the total came to $411.10, or $126.90 less than fuel injection. And then there was the output to consider: The fuel-injected 327 was rated at 375 hp and 352 lb-ft of torque, while the 396 delivered 425 hp and 415 lb-ft of torque.
Fuel injection was dropped from the Corvette’s list of options after the 1965 model year, and wouldn’t reappear until the introduction of throttle-body fuel injection in 1982. The 396 was a single-year Corvette option as well, replaced by the Mk IV 427 in 1966, which made 425 hp and 460 lb-ft of torque in L72 trim. The 427 (in various outputs) would remain in the Corvette lineup until 1970, when it was replaced by the larger-still 454.
The 396/425 Turbo-Jet display engine will be offered at no reserve in Scottsdale, and, while Barrett-Jackson has not provided a pre-auction estimate, a similar cutaway Turbo-Jet 427 V-8 (displayed towards the end of the New York World’s Fair in 1965) sold in December 2015 for a fee-inclusive $132,250. Another cutaway Chevrolet V-8, this one a 350 Turbo-Fire from a 1973 Camaro Z/28, sold at the same 2015 auction for a fee-inclusive $74,750.
The Barrett-Jackson Scottsdale sale runs from January 12-20 and takes place at Westworld of Scottsdale. For additional details, visit Barrett-Jackson.com.