On June 20, 1980, Terry Kennedy picked up 6 ribbies with a pair of three-run home runs in a 7-5 win over the Reds in Cincinnati. With the team up 1-0 in the first Kennedy got a hold of his first bomb of the day to cap off the 4 run inning. However, the Reds fought back with three runs in the third then a two run shot by Dan Driessen in the sixth that gave Cincy a 5-4 advantage, it was an advantage that wouldn't last long. The seventh inning opened up with a pair of singles, then Kennedy went yard again, this time he gave the Redbirds a lead they would not relinquish.
Check out the box score: http://www.baseball-reference.com/boxes/CIN/CIN198006200.shtml
You can watch a virtual game here: http://www.backtobaseball.com/playballregularseason.php?page=0&IDindex=CIN198006200&date=June+20%2C+1980 I really enjoy this website, all kinds of great games on there.