For some reason, I've never associated the Cadillac with auto racing. The website I visited had quite a bit of interesting info on this particular model year. Some excerpts:

Not only did the new engine give the car unequalled performance and ability, but it did so at a substantial gain in fuel economy. The engine weighed in nearly 200 pounds less than the old L-head, but because it was cooler running it required less radiator mass, making the savings in weight even greater (220 pounds).

The engine was a sensation, so much so that it was rushed off to race tracks across the country. Almost-stock Caddys with big racing numbers plastered on their sides were seen roaring down race track straightaways within a few short months after the '49 models bowed. The cars were so hot that famed Briggs Cunningham took the Caddys racing, even to the 24 hours of Le Mans in France. There, a near-stock Coupe de Ville finished tenth overall against the world's finest racing machinery. The British Allard Company even used the engine in its new J-2 sports/racing car.

The new V-8, under constant development even after introduction, could handle these, so the first major redesign wasn't deemed necessary until 1964.

The link: http://100megsfree4.com/cadillac//cad1940/cad49s.htm