Abstract: Method and apparatus for configuring a pressure relief valve to have a desired internal orifice size. A population of nominally identical inserts are provided having different internal orifice diameters. A resilient seal ring is placed upon a selected insert and both are inserted into a cup-shaped seat body to form a valve seat assembly. The valve seat assembly is secured within a housing of the pressure relief valve in facing relationship to a moveable piston assembly which is biased against the seal in a normally closed position. When a new internal orifice size is desired, the insert is removed and replaced with a new insert having the new desired orifice size. No changes are necessary in the remaining components. The resilient seal preferably comprises a stiffener ring of rigid material surrounded by an annular ring of resilient material.