Junkyard Treasure: 1981 Cadillac Fleetwood Brougham Coupe with V8-6-4 engine

An extremely rare example of Cadillac's too-far-ahead-of-its-time cylinder-deactivation system

The Cadillac Division hit a big home run in 1949 with its new 331-cubic-inch overhead-valve V8, a technological masterpiece that left the flathead-equipped competition grinding their teeth down to bloody stumps in frustration. The final member of this engine family was supposed to be a huge technological leap forward: a 368-cubic-inch version with a futuristic cylinder-deactivation system that would keep those troublesome Middle Eastern oil producers at bay with its ability to run on four or six cylinders when appropriate. Sadly, computers of the era weren't good enough to make the L62 V8-6-4 engine run right, and the whole thing turned out to be a costly disaster for GM. The V8-6-4 debuted in the 1981 model year, and examples of these cars are incredibly rare today; this Colorado car is the first junkyard V8-6-4 Cadillac that I have seen in the last 20 years.

This badge now adorns my garage wall.

Murilee Martin

1981 was the only model year for the V8-6-4 in regular passenger Cadillacs, although buyers of limousines and commercial chassis could get this engine through 1984. Interestingly, the base Cadillac engine in 1981 was the (nearly-as-trouble-prone) 350-cubic-inch Oldsmobile diesel; a 252-cubic-inch Buick V6 was optional. The V8-6-4 was rated at 140 horsepower in 1981, which gave the 4,069-pound Fleetwood Brougham Coupe a power-to-weight ratio just slightly better than that of the Chevrolet Chevette Scooter (and much worse than that of the notoriously pokey 2018 Mitsubishi Mirage). Torque was decent enough— 265 lb-ft— to give nearly-tolerable acceleration.

Here's how you can identify a V8-6-4.

Murilee Martin

The Eaton-designed cylinder-deactivation scheme in the V8-6-4 involved solenoids on the rocker arms of two cylinders per bank, disengaging two or four pairs of rockers when needed. This hardware fit beneath distinctive-looking bulges on the valve covers, as seen in this photograph. The owners of most of these cars simply disconnected the electrical controls for the cylinder-deactivation system, making the car a fuel-swilling full-time V8.

Decades of outdoor storage have trashed the interior beyond reasonable hope of salvage.

Murilee Martin

The list price of a 1981 Cadillac Fleetwood Brougham coupe was $15,942, or about $45,000 in 2018 dollars. A 1981 Lincoln Continental Mark VI coupe went for $16,858 and a 1981 Chrysler Imperial coupe for $18,311; meanwhile, high-rollers who insisted on a German luxury coupe had to shell out $31,980 for a new BMW 733i or $46,638 for a Mercedes-Benz 380SEL S-Class.

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