When Supernatural Thrillers began in 1972, it was adapting material from well known authors and classic stories.
In 1973, ST #6 featured the tale of the Headless Horseman. A nice cover by Gil Kane highlights the action against Ichabod Crane. The original artwork for this is a knockout! Kane left room for the logo on top, but the way he positioned the drawing and captured the scene in action was masterful.
Here is the artwork with the cover copy pasted up. You gotta love the mascot for this series in the upper left--a dog (or wolf?) howling at the moon.
And the cover as originally published in full color, where the horse looks demonic as well. The interior story by Gary Friedrich and George Tuska attempted a modern take on the legend, which is why the cover blurb read He Haunts The Midnight Hills -- Today! Nuff Said!