Superheroes Weekend actually consisted of two separate 6-hour marathons, one on Saturday and one on Sunday. Saturday's marathon aired from 12:00 PM to 6:00 PM and consisted of 12 episodes of Super Friends. Sunday's marathon also aired from 12:00 PM to 6:00 PM and consisted of 12 episodes of SWAT Kats: The Radical Squadron. Throughout the entire event, viewers were also given special sneak peeks at the upcoming Toonami block.
Oddly enough, neither of the two series featured in the weekend marathon were scheduled to be a part of the upcoming Toonami block. In fact, SWAT Kats never appeared on Toonami throughout the block's 10+ years on Cartoon Network. However, Super Friends did make a brief appearance on Toonami, over a year after this event, in late 1998.