Arguably more stunning than the Two- Rotor XP-897GT was the so-called "Four-Rotor Car" that appeared a bit later in 1973. Built on the first XP-882 chassis under the aegis of company design chief Bill Mitchell, it carried a pair of GM's experimental two-rotor engines bolted together into a 420-horsepower "super Wankel." A Corvette-like face and obvious high performance potential were taken as strong suggestions that GM was brewing a radical new Corvette for the late Seventies or early Eighties.