Mercury - Gear Housing Assembly - Silver - Cambered- Counter Rotating - XXL - Torpedo Lower Units Only - 8M0142327. See below for applicable engines: 250 HP 4.6L V8 Verado - Serial number range 2B529482 and Above 300 HP 4.6L V8 Verado - Serial number range 2B529482 and Above 300 HP 4.6L V8 Verado SeaPro - Serial number range 2B529482 and Above 300R HP 4.6L V8 AMS Racing- Serial number range 1E081459 and Above