Abstract: A shear ram-type blowout preventer for severing and sealing a drill pipe string comprises a housing having a throughway for receipt of the drill pipe. Opposed first and second ram assemblies are mounted in the housing on opposite sides of the throughway for reciprocation laterally inwardly and outwardly. Each of the ram assemblies comprises a carrier connected to a drive member for effecting such reciprocation, and a ram block carried on the laterally inward side of the carrier. The maximum thickness of the block is generally equal to the maximum thickness of the carrier measured longitudinally of the throughway. The first ram assembly comprises a blade member carried on the ram block and including a cutting portion extending generally laterally inwardly and a mounting shank extending generally upwardly from the cutting portion. The shank is attached to the ram block by generally horizontally disposed pins.