What the heck am I doing wrong with this '74 Valiant hood?

I agree with @MV8.

If it can't be straightened then the search is on for a replacement.
I bit the bullet and bought replacements. I had no confidence I could pull my originals back into shape, especially with no real way of knowing what shape they are supposed to be. Once the replacements arrive, I'll do a comparison and document it here. At that point, I may try pulling the originals into shape.