About a month ago, I came across a story about a minor leaguer who hit a 733 foot home run 50 years ago. I was suspicious. There is a site out there called Hit Tracker Online that has been keeping track of major league home runs for the the last five years. The only one that topped 500 feet was by Adam Dunn on September 27, 2008. I'm assuming the fifty year old shot was measured like a golf shot and bounces and the roll counted.
FWIW, Dunn strikes out a lot, but when he connects, the ball carries. He might have the record over the past five years for blasts that cleared the fence by at least 20 vertical feet AND landed at least 50 feet past the fence. Rabbit Maranville All-Star? I think home runs started getting cheap over the past 15 years, but these may be worth watching.