Mercury Head Gasket 2.4L, 150 Magnum II OB242885 - OC239552, 150 XR4 OB242885 - OC239552 WSM 505-42 OEM# 27-41246-1 High Performace Quality OEM Style Gaskets. Gaskets and seals meet OEM standards or higher. PWC Engine brings Higher Quality for an awesome price! Complete kits include crankshaft oil seals.