“Later on they tend to get longer than they really were.”
As quoted in "IT'S OUTTA HEEERRE!!! : A New Generation of Sluggers Invites Tape-Measure Comparisons" http://articles.latimes.com/1986-07-21/sports/sp-26487_1_home-run by Ross Newhan, in The Los Angeles Times (Monday, July 21, 1986)