All Gustavson credits verified and courtesy of Terry Gustafson, son of Paul Gustavson.
The art is similar the many Manhunter stories in Police Comics (Quality, 1941 series) credited to Riss.
Bob Hughes agrees on Riss pencils.
The two lines between chin and jaws, making him look a bit fat, narrow skull and round lower lip in sideview on Black X, make this the art of Quackenbush. Compare with his signed stories in previous issues.
text story
Originally credited "Sam Citron ?" Similar art to the credited pencil work on Manhunter stories in Police Comics #37-#59 by Peter Riss.