Hi guys, newbie here so this is my first question... how much HP will the SX drive handle? I would like to modify my stock 320 HP 350 CID Volvo Penta in my 2003 225 LPX Crownline.

They're plenty strong. One of my employees is running a blown small block in front of one turning a 25 mirage+ with no issues. Merc/Quicksilver makes a hub adapter to run the Merc props.