I’m grouping these unrelated two stories together because they both have something in common: They’re pretty bad.
First, issue #90: In the panels above, Odin cockblocks Don Blake, stopping him from telling Jane Foster that he’s really Thor. An adventure happens, but it’s lame. And then, at the end, he breaks the fourth wall.
If you’re thinking that the art doesn’t look good anymore, that’s because Jack Kirby’s gone.
In #91, we get the first appearance of valkyries.
Thor fights a magician named Sandu, who tries (and fails) to lift Mjolnir. Which still isn’t called Mjolnir yet.