RPO-code ZR1 has a solid significance in the history of Corvette, having proclaimed the pinnacle of Corvette small-block performance in 1970-1972 and 1990-1995. (The current ZR1 designation actually refers to a model, not an option package, but the basic naming convention still applies.) That's the back story of why Bennett Coachworks of Milwaukee, Wisconsin, named its new C6-based supercar the ZX.
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