The Cadillac V-series, like Mercedes-Benz’s AMG models, M-badged BMWs, Audi’s RS models, and Lexus F models, is a high-performance riff on a luxury car. While the Vs are relatively new, arriving only in 2003, the idea goes way back to before this 1978 Cadillac Seville was a new car. AMG began modifying Mercedes products back in 1967, BMW embraced the concept in 1972, Audi joined in for 1990, and Lexus is the newcomer, starting only in 2006.
Even back in the dark days of the late 1970s, it’s easy to imagine a proposal at Cadillac to meet Mercedes and BMW on their own turf. After all, that’s where the Seville concept came from to begin with—it just didn’t go all the way into the high-performance realm. Still, because the Seville’s K platform was essentially a stretched X platform (basis of the Chevrolet Nova, Pontiac Phoenix, Oldsmobile Omega, and Buick Skylark and related to the F platform of Camaro and Firebird fame), it wouldn’t have been an insurmountable challenge to build a hot version of the Seville
When the STS-V (derived from “Seville Touring Sedan”) came out in the mid-2000s, it didn’t use the Corvette-spec LS-series V-8 like its CTS-V predecessor. Instead, it used a 440-hp version of Cadillac’s own Northstar engine.
Would it be fair, then, to replace the 180-hp 350-cu.in. Oldsmobile-designed V-8 in this Seville with its 455-cu.in. big brother? By 1978, the 455 was no longer in production for cars, but it still could be had for motorhome, industrial, and marine applications. Because it shares architecture with the 350, a 455 would be a more straightforward swap than the contemporary 195-hp, 425-cu.in. Cadillac V-8. The Holley EFI (replacing the factory’s Bendix setup) should transfer right over.