Classic Teen Titans vs Classic X-men

[Steel Inquisitor]

Both are from their first eras in comics.

Teen Titans: (Wolfman and Perez)
Robin (Grayson), Flash (Wally), Raven, Starfire, Wonder Girl, Cyborg, Beast Boy

vs


X-men: (Lee and Kirby)
Cyclops, Angel, Marvel Girl, Iceman, Beast


or

X-men (Wein and Cockrum)
Wolverine, Storm, Nightcrawler, Colossus, Sunfire, Banshee, Thunderbird 1

[Beadle]

Pretty sure any of Wally, Donna or Kory could solo against the Lee/Kirby team.

Donna could probably also solo the Wein/Cockrum team. Not sure whether that era of Kory or Wally could hurt Petey though (but Petey isn't hitting Wally either).

[Sharpandpointies]

Wally takes out everyone but Peter, and the resulting dogpile is too much for him to handle.

Alternately, Raven deals with Peter pretty decently.