In 1980, Excalibur introduced the Series IV, marking a significant departure in the visual identity of the Milwaukee, Wisconsin marque. Departing from the SS/SSK inspiration, the new design took cues from the 500/540K series of vintage Mercedes-Benz.

The ladder-type chassis, remaining largely unaltered from the Series III, underwent a 13-inch extension. Boasting four-wheel independent suspension, front and rear anti-roll bars, four-wheel disc brakes, a Positraction rear end, a capacious 30-gallon fuel tank, and an all-stainless dual exhaust system, the Series IV epitomized the pinnacle of Brooks Stevens’ automotive vision in terms of refinement and luxury up to that juncture.

Powering the Series IV cars was the widely used 305-cubic-inch General Motors V-8 engine, akin to those found in contemporary Camaro, Corvette, and Trans Am models. This engine delivered 155 horsepower to the wheels through a Turbo-Hydramatic 400 automatic transmission. Despite diminishing performance due to stringent Federal regulations, consumers readily embraced the trade-off for unparalleled comfort and modern features.