That was with the 3 blade propeller, she now has a 4 blade prop. and runs 500 - 600+ MPH.
Um, 500+ yes.. 600+ no.. Via Wikipedia:
The record for the fastest single-engined piston plane is held by a modified Grumman F8F Bearcat, the Rare Bear, with a speed of 850.24 km/h (528.31 mph) on 21 August 1989 at Las Vegas, Nevada.
The 3 bladed prop on Rare Bear was actually better for straight line speed.. They made the Bear back to the 4 bladed prop to help it go around the corners of the reno pylons. So I heard..