As of September 2006, the Allen brothers ranked 11th in the MLB brother-combination, home run list with 358 dingers (out of more than 350 combinations all-time).

He was dealt along with minor-league infielder John Ryan from the Brewers to the Atlanta Braves for Bob Tillman at the Winter Meetings on December 2, 1970.

In 1989, he became the first African-American trainer in seventy-eight years to saddle a horse in the Kentucky Derby when Northern Wolf ran sixth to winner Sunday Silence.

[4] In June 1990, he conditioned Northern Wolf when the horse set a new Laurel Park track record of 1:08 4/5 for six furlongs while winning the Duck Dance Handicap.

[6] Allen remained in baseball as a scout, latterly serving the Houston Astros at the professional level and based in Upper Marlboro, Maryland.