Abstract: A drilling head with an upper body assembly removably clamped onto a stationary spool via a bayonet-type coupler clamp rotated into clamped and unclamped positions by a remote controlled hydraulic motor connected to the clamp by a ring and pinion gear. The upper body assembly has a kelly bushing, a corrugated drive bushing rotatable with the kelly bushing, a drive ring rotatable with the drive bushing a bearing assembly surrounding the drive ring, and an elastomeric stripper connected to the drive ring for rotation therewith. The stripper is adapted for sealing engagement with a rotating kelly drive which slides down through the drilling head. Quick connect/disconnect lubrication fittings on the clamp and upper body assembly are releasably mated upon rotation of the clamp to the clamped position to provide lubrication from a single lubrication line to both the bearing assembly and seals via passageways formed in the outer body of the upper body assembly.