N54: Oil Viscosity & Rod bearing clearance N54

Not to make this yet another oil thread but...

since i spun a rod bearing last season I've been wondering what the best viscosity oil is to be used in a high hp, stock block with stock rod bearing clearance?

-currently running german castrol 0w40 on this motor

-the motor which spun a rod bearing last season was running liqui moly 5w40

curious what your thoughts/opinions are on this and what you think are the main culprits of spun bearings in these engines



thanks