This cover is based on the splash page of "Heart of Stone" from I Love You (Charlton, 1955 series) #121 (December 1976).
This story looks to be by a Spanish artist, in the Selecciones Ilustradas style. Note the spelling of "Parck" on page one (corrected on the cover), suggesting art from non-English background. The art doesn't look like Charlton's main spanish artists, Demetrio Sanchez Gomez and José Luis Garcia-Lopez. Perhaps Jorge Badia Romero, whose work is reminiscent of José Gonzalez, as this is.
The signature on this story looks like "R. Garcia".