When Richie, Potsie and Malph are caught with a gang's girlfriends, they walk by the "stoop" made famous by Laverne and Shirley.
While Richie and his friends are in Eastchester, they stand outside a store with an advertisement in the window for "Bliss Cough Syrup". The exact same advertisement was seen in Bewitched as a major part of the storyline five years earlier.
When Fonzie rolls up on his bike to confront Dooley and the Dragons with Richie, Ralph and Potsie, the mirrors on Fonzie's bike are at weird angles to the point where he can't see out of them. The mirror on his left side is facing the ground.
Richie's favorite breakfast is blueberry pancakes. Howard's favorite is omlettes.