The artist, “S.R. Powell”, is the same Bob Powell that did comics in the 40s and 50s. He was probably best known for the horror stories he did with Harvey Publications. He was the art director for SICK during most of its run until his death in 1967.
They relied on many golden-age comic artists. Founder Joe Simon was himself one. A former partner of Jack Kirby's that went on to become publisher of the comics they started.