The Kentucky Mountain Boys were not a separate group as Discogs shows. J.D Crow formed "J.D. Crowe & The Kentucky Mountain Boys" as a group, which was the prototype for J.D Crow's "New South", see https://en.wikipedia.org/wiki/New_South_(band) . "Rusty York and the Kentucky Mountain Boys" was a studio group that recorded four extended play albums of six songs each, see http://www.rockabillyhall.com/RustyYork1.html .