Originally posted by Surtur
I dunno, are we assuming this is just a magical PC Superman? If so he has a major speed advantage.
Basically, Cap had true invulnerability in that era. The only way Black Adam and him could beat one another is to exploit the magic lightning transformation, the same way modern Cap uses it like a weapon on Superman.
Which he can also do, btw. Cap got Supes covered in parts of a radio tower and prepared to call in the lightning, before Shazam used astral projection/tp to tell him to let Superman win (To break mind control forcing them to fight, which Cap was eventually able to shrug off but Supes could not..)
Also, DC had Cap as completely invulnerable and immune to fatigue in Earth S, just like in the golden age, so the fight took place on Earth 1 where he's "merely" as powerful as Silver Age Superman.