Hi, To help ensure the correct parts it would be best to know what exact 5.7 GS engine model you have as there are a few possibilities specially being a year 2000 boat. Is the engine color painted red or charcoal gray? See the following link for more info of how to obtain more engine info, http://www.volvopentastore.com/mall/template/store/volvopenta/help.html
You're looking for something like 5.7GSPEFS as an example.
The Volvos of that era may use the same thermostat housing as OMC used prior to the Volvo joint venture years (1994-1998) and they use the same stats too. It is a 160* stat that is held into the 'stat housing with a rubber ring.
