BDS pressure diversion valve assm. This valve is a must if you are going to use an automatic transmission with a blown motor. It will give the vacuum modulator on the transmission the correct vacuum signal until the motor begins to build boost. This will allow the tranny to do proper shifting and if not used it can burn up a tranny fairly quickly. The top line goes up to the base of the carb and the .125" npt goes to tranny modulator and the .187 line hooks to the blower manifold. The pdv valve is made from billet alum. then polished and includes mounting hardware as well as hose barbs.