The show's resident bullies were supposed to be teenagers, but Bart Braverman (Ace) was 31 and Larry Larsen (Duncey) was 38.
The role of Mongo was created for Alex Karras, who played a character with the same name in Der wilde wilde Westen (1974). The producers negotiated with Karras, but when they couldn't reach an agreement, the part ended up going to Lennie Weinrib.