Dear Dennis;
Most of us run solids in our land based Hot Rods.
I would stay with what the factory put in your marine engine & solve the 'problem' you have.
My guess would be that they (lifters) only need a proper adjustment. Remember; tighten one more turn after 'zero'. This is the most common mistake.
Your in a cold climate, so run multi-grade oil too.
Good luck.
