Cadillac has been offering big V8 engines for more than a century, none of them bigger than the mighty 500 CID V8 of 1970-76. 

When General Motors announced in April of 2021 that its flagship Cadillac brand was on its way out of the internal-combustion business to focus exclusively on electric vehicles, it was good for a moment of historic reflection. Cadillac has been producing gasoline vehicles for almost 120 years, and for more than a century now, the division’s product line has included V8 engines.

Depending how you break them down, there have been at least eight generations of Cadillac V8s, each with its own memorable features. One engine that stands out for its sheer size if nothing else is the 500 cubic-inch V8 of 1970-76—the largest displacement for an American passenger car engine of the modern era.

While the 500 CID Cadillac V8 arrived on September 18, 1969 at the acme of the Detroit muscle era, it was by no stretch a muscle car engine. Rather, it was built to move Cadillac’s increasingly massive luxury sedans, then topping the 2.5-ton mark. Optimized for silence, smoothness, and fistfuls of low-rpm torque, the 500 was essentially a stroker version of the 472 cubic-inch V8 introduced in 1968, with its crank swing increased from 4.06 inches to 4.304 inches. Coupled to a bore of 4.30 inches, the total displacement came out to precisely 500.02 cubic inches, or 8.2 liters.  The 472 was clearly designed from the start with room for expansion, with 5.0-inch bore spacing and more than 10 inches of deck height.

The initial 1970 version, offered only on the giant Fleetwood Eldorado coupe, featured a sporty 10:1 compression ratio and was rated at 400 SAE gross hp at 4400 rpm. Of course, the eyebrow-raising figure was the torque rating: a mighty 550 lb-ft at just 3000 rpm. But the giant V8 was not a particularly efficient package (despite a surprisingly modern-looking combustion chamber, in hindsight) and the versions that followed were crippled by progressively stricter emissions tuning.

By 1975, when the 472 was discontinued and the 500 was offered on all Cadillacs (except Seville) the output was only 210 hp (SAE net). For 1976, the 500’s final year in production, output was a mere 190 hp—less than a decent 2.0-liter four can do these days. For 1977, the Cadillac V8 was shrunk down to 425 cubic inches, then downsized again in 1980 to a mere 368 CID package (which included the notorious V8-6-4 version featured here). By 2030, Cadillac plans to be offering electric vehicles exclusively.