Curbside Classic: 1980 Cadillac Sedan DeVille – Et Tu, Brougham?

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(first posted 2/9/2015)    Friends, Romans, CCers, lend me your ears! I come to praise this 1980 Cadillac Sedan DeVille despite its decrepit exterior condition, not to bury it. The evil of a car design lives after it, the good is often forgotten and sent to the junkyard with it, but let us not allow that to happen with this Malaise Era Cadillac.

This Sedan DeVille is one that I have seen parked on the same street in Washington, DC, near Georgetown University, since the early 1990s; from time to time driven and then re-parked on the same street, gradually becoming more ragged as the years passed, but still alive and running. After this car’s 34 years of existence and my over two decades of seeing it, I have come to speak of what I know about its story.


The downsized 1977 Cadillac DeVille and Fleetwood Brougham continued much of the basic engineering of their enormous 1971-76 predecessors beneath their trimmed down bodies.  The unique Cadillac V-8 continued, reduced in displacement from 500 to 425 cubic inches.  Output was a respectable 180 horsepower and 320 ft-lbs of torque with a carburetor or 195 horsepower and 320 ft-lbs of torque with the optional electronic fuel injection introduced in 1975, and the (unadjusted) EPA mileage rating was 14 mpg city/20 mpg highway.

With 138,750 Sedan DeVilles, 95,421 Coupe DeVilles, and 28,000 Fleetwood Broughams sold in 1977, a considerable increase over the 114,482 Sedan DeVilles, 67,677 Coupe DeVilles, 6,200 Calais sedans and coupes, and 24,500 Fleetwood Broughams sold in 1976, the market had clearly spoken that the 1977 DeVille and Fleetwood Brougham were right for the times and a success.

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The 1980 DeVille and Fleetwood Brougham tweaked the concept further with a more aerodynamic restyling with a more formal roofline that remained almost completely unchanged through 1989, and a Cadillac big block V-8 with displacement further reduced to 368 cubic inches.  Retaining the same 4.06″ stroke, it reduced the cylinder bores from 4.082″ to 3.80″. Output now was 150 horsepower and 265 ft-lbs of torque at a barely above idle 1600 rpm from the only version, which used a carburetor with no fuel injection available (digital electronic fuel injection was an Eldorado and Seville-only feature).

Using the same 3-speed THM400 transmission, the EPA gas mileage rating now was 15 mpg city/23 mpg highway.  Part of the credit for the mileage rating goes to the ultra-low 2.28:1 final drive ratio used since 1977, introduced along with the 425 and still usable with the 368 with its high torque from just above idle speed.


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For comparison, the only German sedan in close to the same class in size and engine configuration and displacement, the W116 chassis Mercedes-Benz 450SEL, had an EPA rating under the same test protocols of 16 mpg city/22 mpg highway.  With its single overhead cam, fuel injected 4.5 liter (275 cubic inch) V-8, smaller and more sophisticated than Cadillac’s pushrod-operated overhead valve, carbureted 368 cubic inch V-8, it had essentially the same fuel consumption as the Cadillac.

The shorter wheelbase, six cylinder Mercedes-Benz 280SE paradoxically had a worse mileage rating of 16 mpg city/20 mpg highway, from its 2.8 liter double overhead cam M110 inline six whose low power and poor fuel economy led to diesels becoming the preferred U.S.-market Mercedes engines in the W116 and W123 series.

The Mercedes 4.5 liter V-8 no doubt had advantages in power to weight ratio and peak rpm, and Mercedes’ four-wheel independent suspension was more sophisticated, but in a luxury sedan with a typical driver of such a vehicle during the era of 55 mile per hour highway speed limits, these theoretical advantages probably rarely affected real-world driving.

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Few remember 34 years later, but the 1980 Cadillac DeVilles and Fleetwood Broughams — both now available for 1980 as either a four-door sedan or a two-door coupe — had not only enormous interior space and considerable “presence,” but also both surprising fuel economy, and proven reliability and durability from the well-established Cadillac engine under the hood.

It had been a success from its introduction as the 472 V-8 in 1968, and it had evolved gradually for over a decade as the 500, 425, and finally 368.  The 368 of 1980 was the last successful general usage of this engine, which acquired the unreliable V8-6-4 electronic controls in 1981, then disappeared in favor of the infamous HT4100 aluminum block V-8 in 1982 except in Fleetwood Limousines and commercial chassis, which used the 368 to move their longer and heavier bodies until 1984.

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Identifying the year of this Sedan DeVille was initially difficult because it had no badges on its flanks or trunk lid identifying the engine, announcing “V8-6-4” or “HT4100 Digital Fuel Injection” or “5.0 Liter.”  Some research to determine the year of the grille told me why there were no engine badges — this car came from the end of the era when a full size DeVille or Fleetwood Brougham had a Cadillac engine standard, not any of the engines that ruined Cadillac’s reputation with their unreliability, lack of power, or both.

The first dagger came in 1978, with the introduction of the ill-fated Oldsmobile diesel V-8 as an option; a further one in 1981, with the addition of the unreliable V8-6-4 electronic controls to the 368; and the lethal blow in 1982, with the across the board introduction of the underpowered and unreliable HT4100 aluminum V-8 as standard.

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The Oldsmobile 307 V-8 that took over as the powerplant for this body style as the “5.0 Liter” in the Cadillac Brougham, in 1986, restored reliability to the engine compartment, but its reduced displacement and power (140 horsepower and 255 ft-lbs of torque) came with an only slightly improved EPA rating of 18 mpg city/25 mpg highway (16 mpg city/23 mpg highway under the current rating system), even with the benefit of the four speed THM200-4R.

Instead of again having more than adequate power from a Cadillac engine, the Brougham would continue with a non-Cadillac engine barely able to move it — a final disappointment.  Et tu, Brougham?  Then fall, Cadillac!


So here we have a Sedan DeVille from the last of the traditional and fundamentally sound years, with current inspections and registrations and still at least occasionally driven after 34 years.  The car has certainly lived a good life, and from the looks of the blue velour interior (identical in color to the interior in this brochure), so has its owner.

The interior had a unique feature that I have not seen before on any car, which reflections on the windows unfortunately did not allow me to photograph: a front seat with completely even wear on the driver and passenger sides.  The driver of this car rarely if ever went anywhere alone; he or she apparently always went places together with either a spouse or friends.  We all should be so lucky.


The driver and passenger spent all of those trips over the course of 34 years in comfort.  With enormous interior and trunk space, soft leather or velour, automatic climate control, and power everything, Today, critics seem obsessed with 0-60 times and whether the wood grain was from a tree or made of plastic.  The owner of this car probably did not care about either, and with good reason.

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There are probably many 1980 DeVilles and Fleetwood Broughams that have led similar lives as reliable and reasonably economical luxury cars in anonymity, out of the 55,490 Coupe DeVilles, 49,188 Sedan DeVilles, 29,659 Fleetwood Brougham sedans, and 2,300 Fleetwood Brougham coupes produced that year.

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At least a few enthusiasts have seen further potential in these cars and acted on it.  One was Matt Garrett, a collector with an impressive collection of Cadillacs, who built an extreme yet stock-looking luxury muscle car from a 1980 Fleetwood Brougham D’Elegance with a factory Commercial Chassis frame and Astroroof, powered by a 500 horsepower 500 cubic inch Cadillac big block and with Caprice 9C1/Impala SS suspension upgrades.

It was comparable to the renowned Mercedes-Benz 450SEL 6.9, with its big-block 6.9 liter M100 engine, but far more powerful and faster.  So although this white 1980 Sedan DeVille may never be considered worth restoring, out of the many who once loved these Cadillacs — not without cause — some mourn their passing and have preserved examples that remind us of what these cars once were and could have been.