Welcome aboard. A factory manual will be your best source for information.
The drive should be removed at the end of every season for inspection of gimble bearing and u joints. Gear lube should be drained and changed as well.
Every 2-3 years the raw water pump should be replaced as a preventative maintenance.
As for oil filter, plugs, etc. The GM block and heads is same for OMC as well as Volvo and Merc.
Iboats has all your tune up components
