I would stick with OEM oil
Last year I couldn't locate a Westerbeke
labeled filter and went with a Sierra, cross-referenced P/N, at the same price
. After 20 hrs the o-ring blew dumping 7 quarts in the engine
pan. Thinking it was an installation
problem I installed another Sierra which blew right away.
Sierra refunded my money
but claimed they couldn't find anything wrong with their filters. My analysis showed a difference in gasket
dimensions. They asked to see my findings which I sent but since they never got back to me I suggest sticking with the OEM product.