●For All GM LS Series Engines. ●100% quality assurance tested, more responsive, less expensive, easier to install. ●INSTALLATION-- These can be installed on the front or rear of the cylinder heads. ●HIGH QUALITY-- Constructed with billet aluminum with natural finish, which is anti-rust and durable to use. ●Passengers side port adapter has two 1/8"npt ports, drivers side port adapter has one 1/8"npt port.