According to Official Guinness Records,
On 21 August 1989, in Las Vegas, New Mexico, USA, the Rare Bear, a modified Grumman F8F Bearcat piloted by Lyle Shelton (USA), set the Fédération Aéronautique Internationale-(FAI-) approved world record for a 3 km (1.8 mile) course of 850.24 km/h (528.31 mph), and in doing so became the fastest piston-engined aircraft.The Rare Bear is a restored and modified WWII era Grumman F8F Bearcat, complete with a Curtiss-wright R3350 engine which produces in excess of 3,000 kW (4,000 hp).
For a complete list of 1989 records, please visit 1989 Guinness Records in United States.