Apparently King Kong fought King Ghidorah once, in sonorama form.
I don’t know much about that particular sonorama, but I do know the art was by Takashi Minamimura, one of the most iconic of all kaiju illustrators. He did a lot of sonorama paintings, and sometimes that included King Kong.
I don’t know for certain that these are his, but they sure look like it:
He also did this set giving behind-the-scenes details regarding The King Kong Show, published in Shonen Magazine (images pilfered from Pink Tentacle).
While we’re at it, let’s throw in this one from Takayoshi Mizuki, showing Dr Who’s base.
The illustrations were evidently popular enough to get merchandise, as well, distinct from the version of Who and Mechanikong in King Kong Escapes. It’s not terribly different from the cartoon, but enough so that Minamimura gets the credit.
As a caveat, he also has some pretty racy paintings (mostly published under other names), so if you’re just looking for monster/superhero stuff, be aware that you might stumble across a dominatrix or two in his portfolio.