ACTION COMICS (1938) #746

Superman’s new powers provide a tempting target for the villain who craves an upgrade to his own malevolent might-Metallo! Although Superman has defeated him before, now he must beat Metallo with his new powers-the very thing that Metallo is using to boost his own abilities to the max! Part 3 is in Action Comics #747 « 1998 27 »–Triangle in upper left hand corner.