On my boat I always used the OEM Mercruiser exhaust parts, replacing them for internal corrosion every 3-5 years and performing an annual disassembly for internal inspection.
At the last replacement cycle I had enough and redesigned the exhaust using OEM Mercruiser parts, from impossible to drain and impossible to flush, to now permitting me to drain, then flush w/ fresh water, soapy water, then Salt Away, followed by draining bone dry, ready for the next usage.
My last annual disassembly for internal passage inspection after four years of usage revealed that these parts still look brand new.
My expectation is that these parts will now last the life of the engines.
