Marine engine oil

Hi guys I’m just after a bit of advice regarding engine oil

I am running a pair of LS2 alloy block engines in my boat they have standard crank but forged pistons and rods with LS7 cams and cnc heads running approx 490-500hp on the engine dyno

what oil would people recommend as they can run at 4000+ rpm for extended lengths of time and obviously there is a lot of load on them I have been running them on miller oil’s css 10w/40 which is a semi synthetic here in the uk which was recommended to me but wondered what everyone’s thoughts were?

Im a fan of Mobil 1 0w/40 in my normal road cars but I don’t know if it would cut it in a marine environment

Thanks

Si

The Millars you are using will be fine, I have tested many well-known oil brands in customers marine applications from mild to wild and have found no bad oils as long a you have the correct grade which i believe you have you will be fine

regards Ross

As Ross said, you should be fine. What may be more important is the oil temperature and change hours.

Cheers for the reply’s I will stick to what I have oil gets changed every season so probably every 20-25 hours

Thanks

Si