This combination proportioning valve is for Disc / Disc applications. This valve performs all the necessary functions when using disc brakes in the front and disc brakes in the rear including the following.
GM Proportioning Valve Kit Brake Lines Mounting Bracket Disc Disc Chrome PV4
GM Proportioning Valve 4 Wheel Disc Brakes
GM Proportioning Valve Front Disc Rear Drum
GM Proportioning Valve Kit Disc Front Disc Rear Mounting Bracket Lines PV4