1988 Corvette ZR-1 Prototype #EX5023 VIN 1G1YY218XJ5100048 finished in Medium Blue Metallic with a blue leather interior. It was a prototype used by Lotus in Hethel, England, as a test mule for the calibration of the LT5 engine that was in development at the time and is powered by a Phase II LT5 engine.