Godzilla all the way. This movie was a sham. The largest Kong ever got was like, 60 feet tall or something. At his shortest, Godzilla was something like 240 feet. Lol. I understand why they did this, but come on...a nigh invincible radioactive monster who's been alive for millions of years or an overgrown ape? :p
There is only one version despite popular rumors. :) (below is taken directly from the Wikipedia entry on the film. The source is a book about Toho Studios)
Since King Kong was seen as the bigger draw (at the time, he was even more popular in Japan than Godzilla), and since Godzilla was still a villain at this point in the series, it led to the decision to not only give King Kong top billing, but also to present him as the winner of the climactic fight. While the ending of the film does look somewhat ambiguous, Toho confirmed that King Kong was indeed the winner in their 1962/63 company book Toho Films Vol. 8, which states in the films plot synopsis, A spectacular duel is arranged on the summit of Mt. Fuji, and King Kong is victorious.
Gamera
Since King Kong was seen as the bigger draw (at the time, he was even more popular in Japan than Godzilla), and since Godzilla was still a villain at this point in the series, it led to the decision to not only give King Kong top billing, but also to present him as the winner of the climactic fight. While the ending of the film does look somewhat ambiguous, Toho confirmed that King Kong was indeed the winner in their 1962/63 company book Toho Films Vol. 8, which states in the films plot synopsis, A spectacular duel is arranged on the summit of Mt. Fuji, and King Kong is victorious.